lable at ScienceDirect

Animal Behaviour 112 (2016) 285e300

Contents lists avai

Animal Behaviour

journal homepage wwwelsevier comlocateanbehav

Waltzing Taeniopygia integration of courtship song and dance in thedomesticated Australian zebra finch

Robert Ullrich Philipp Norton Constance Scharff

Department of Animal Behaviour Freie Universiteuroat Berlin Berlin Germany

a r t i c l e i n f o

Article historyReceived 11 May 2015Initial acceptance 1 July 2015Final acceptance 13 October 2015Available online 29 January 2016MS number 15-00394R

Keywordschoreographycommunicationcourtshipdancemultimodal signalssongzebra finch

Correspondence C Scharff Freie Universiteuroat BerliGermany

E-mail address constancescharfffu-berlinde (C

httpdxdoiorg101016janbehav2015110120003-3472copy 2015 The Association for the Study of A

Multimodal signalling can improve or maximize information exchange A challenge is to show that twoindependent signals such as vocalizations and visual displays are deliberately coordinated Male zebrafinches Taeniopygia guttata signal visually and acoustically during courtship performing a stereotypeddance while singing The male approaches the female hopping in a zig-zag pattern turning his body axisand wiping his beak repeatedly on or above the perch The only previous quantitative study of song anddance choreography in zebra finches revealed that the distribution of all movements during song was notstrongly patterned across birds but very similar in fathers and sons This raises the possibility thatparticular movements may follow a choreography Here we report that three operationally defined dancemovements lsquobeak wipersquo (BA) lsquoturn-aroundrsquo (TA) and lsquohoprsquo occurred with different frequencies and speedduring singing than during silence BW TA and hops clustered significantly at the start and end of songbouts and were arranged in a nonrandom fashion In addition BW but not TA were performed fasterduring song than nonsong Finally hops coincided significantly more often than expected by chance withparticular notes Together these results suggest that male zebra finches integrate their song and danceduring courtship This may help females to identify courting males in a noisy environment and evaluatethe intensity and quality of the courtship performance Our results underscore that the choreography ofmovement gestures with learned vocalizations such as hand gestures accompanying speech is a furtherparallel between human and avian signalling They invite future investigations into the underlying neuralmechanisms and consequences for mate choicecopy 2015 The Association for the Study of Animal Behaviour Published by Elsevier Ltd All rights reserved

Communication is essential for organizing the social in-teractions of zebra finches Taeniopygia guttata that live in largeflocks (Immelmann 1969) Both sexes use several types of calls butonly males sing songs (Slater Eales amp Clayton 1988 Zann 1996)Males direct their song towards females during courtship but alsosing so-called lsquoundirected songrsquo in nonreproductive contexts egwhen alone or in the company of males (Dunn amp Zann 1996Immelmann 1959 Jarvis Scharff Grossman Ramos ampNottebohm 1998 Morris 1954 Sossinka amp Beuroohner 1980) Malescan rapidly switch between directed and undirected songs (Caryl1981) which differ bioacoustically and in the underlying neuralprocesses (CooperampGoller 2006 Jarvis et al1998 Kaoamp Brainard2006 Sossinkaamp Beuroohner 1980WoolleyampDoupe 2008) Courtshipsong is accompanied by a characteristic dance during which the

n Takustraszlige 6 14195 Berlin

Scharff)

nimal Behaviour Published by Els

male advances towards the female turning 180 with each hoptwisting his head and tail towards the female while continuing tosing When facing the female he also rhythmically swings his headfrom side to side while singing (Barclay Harding amp Waterman1992 Immelmann 1959 Kunkel 1959 Morris 1954 Zann 1996pp 170e174 Fig 1)

When animals use multiple signalling modes to attract a matethose signals need not necessarily be coordinated with each otherin their fine temporal pattern (eg butterfly coloration and pher-omones for mate attraction) However in some animals it has beenshown that courtship can involve two signalling modes that areintegrated into a coherent performance providing the basis for anintegrated percept in the receiver For instance jumping spidersHabronattus pugillis coordinate visual and seismic signals usinglimbs and body appendages (Elias 2006) Golden-collared mana-kins Manacus vitellinus and club-winged manakins Machaer-opterus deliciosus integrate acoustic wing-snaps with visualdisplays during courtship (Barske Schlinger Wikelski amp Fusani2011 Bostwick 2000) Barbary doves Streptopelia risoriaperform visual bows accompanied by acoustic bowing-calls during

evier Ltd All rights reserved

Figure 1 Schematic representation of a male zebra finch courtship dance facing a female bird Reprinted with permission from Morris (1954 p 286)

R Ullrich et al Animal Behaviour 112 (2016) 285e300286

courtship The onset of both signals is not temporally synchro-nized but the intervals between bowing and calling are rhythmi-cally correlated leading to an integrated complex signal (FusaniHutchison amp Hutchison 1997) Male superb lyre-birds Menuranovaehollandiae integrate acoustic and movement signals volun-tarily and within a predictable pattern during courtship (Dalziellet al 2013) Nonvocal bill-clicking patterns and specific songnote sequences in Java sparrows Lonchura oryzivora are closelyintegrated They occur for instance more frequently with thebeginning of song which might be an outcome of cultural trans-mission (Soma amp Mori 2015) In various species female recipientsare known to be sensitive to the multimodality of these signals Forinstance females of the estrildid family have a complex dance inspecies in which males also have a complex dance (Soma ampGaramszegi 2015) Also wing-spread displays in cowbirdsMolothrus ater accompanying song (Cooper amp Goller 2004) elicitlonger lasting copulation solicitation displays from females thanpresentation of song or wing-spread displays alone (OLoghlen ampRothstein 2010) Audiovisual playback experiments revealed thatthe females sexual behaviour varies with the intensity of themales body movements (OLoghlen amp Rothstein 2012) Interest-ingly wing movements and song were integrated even in malesthat had been reared without visual or auditory input from maletutors (Hoepfner amp Goller 2013) Female golden-collared mana-kins are influenced by speed and frequency of the displays bycourting males (Barske et al 2011) Female tuacutengara frogs Phys-alaemus pustulosus prefer a robotic frog that correctly coordinatesthe visual signal of the vocal sac inflation with the produced calls(Taylor Klein Stein amp Ryan 2011) In humans the integration ofgesture and speech is intimately linked to learning and creatinglanguage (Goldin-Meadow amp Alibali 2013) These examples stressthe additive effect of two signalling channels and the relevance oftemporal integration of the two signals with each other In contrastto these examples in other birds visual and vocal displays are notsynchronized For instance long-tailed manakins Chiroxiphia lin-earis and starlings Sturnus vulgaris perform visual and acousticsignals in a parallel but not in an integrated fashion (Beuroohner ampVeit 1993 Lukianchuk amp Doucet 2014)

In male zebra finches it is not clear whether the dance move-ments accompanying song are synchronized to the song The onlystudy that examined whether song and dance are coupled in spe-cific ways found no significant association of stereotypic bodymovements with acoustic features of song (Williams 2001)

Here we operationally defined two dance elements beak wipesand turn-arounds characteristic of high-intensity courtship(Barclay et al 1992) as well as a third dance element hoppingbehaviour and analysed their relationship to vocalizations in vid-eotapes We hypothesized that these movements were associatedwith song more so than when birds were silent We further

speculated that movements were associated with specific positionsin the song motifs

METHODS

Subjects

A total of 20 captive-bred male zebra finches (9e45 monthsold) participated in three variations of the experimental set-upseven in 2010 (experiment A) four in 2011 (B) and 10 in 2013(C) One male was tested twice (2010 2011) and his data wereaveraged Before experiment A male birds were housed in groupsof seven males for several months Birds were transferred fromlarge aviaries into smaller group cages 1 week before experimentsB and C Experiment B was performed in May outdoors andbefore during and after testing birds were also kept outdoorsIndoor conditions were kept at 25 plusmn 3 C and 1212 h lightdarkcycle All subjects had access to seed water grit and cuttlebone adlibitum

Recording

An adult male was introduced to the experimental set-up con-taining one female that he could hear but not see After at least 2 hthe visual separationwas removed for 5 min and themale could seethe female Males that performed courtship dances and directedtheir song to females during this time were audiorecorded andvideotaped During 2 days at least three video sessions per birdseparated by 20 min or more took place All recorded songs weredirected to the female accompanied by the typical courtship-associated movements and body posture We varied the experi-mental set-up during the three experiments with respect to loca-tion cage size and videoaudio equipment which ensured that ourfindings were not affected by the physical constraints of a particularexperimental set-up (Fig 2 Table A1) Because zebra finches in thewild court on branches rather than on the floor we equipped ourcages with a perch in contrast to a former study (Williams 2001)Video and audio streams were digitized and stored on hard disks oron SD cards

Behaviour Definitions Audio and Video Analysis

Audio files (2205 kHz 16 bit resolution) were converted intosound spectrograms using Avisoft-SASLab Pro 438 software(Avisoft Bioacoustics Berlin Germany settings FFT_256 pointsHamming window overlap 50) Video recordings were analysedframe by frame using Noldus Observer 9 XT (Noldus InformationTechnology Wageningen The Netherlands) and dance-associated

30 fps 30 fps

60 fps

25 fps

(a)

(b)

(c)

Figure 2 Experimental set-up for (a) experiment A (b) experiment B and (c) experiment C For experiments A and C males and females occupied two separate plastic-walled cages(51 30 cm and 40 cm high) separated by a removable opaque divider The top of the cage and one of the long sides consisted of transparent plastic material Videos were recordedfrom above and additionally from the front (experiment C) audio was recorded from the side through an opening of the cage For experiment B cages (40 30 cm and 40 cm high)were connected by a 15 m long tunnel (150 20 cm and 30 cm high) containing a single long perch The front of the tunnel consisted of transparent plastic material the other sidesof metal wire mesh Video was taped from the front audio from above The male entered the tunnel at the start of the 5 min test period after an opaque divider was removed Themale and female heard each other in all set-ups but could only see each other through a 17 17 cm wire mesh (experiment A B) or transparent plastic window (experiment C)during the 5 min test period Birds could approach each other to a vicinity of 5 cm but not interact physically During indoor experiments (A C) the cage was illuminated by fourfluorescent lamps (18 W) experiments outdoors (B) were performed under ambient light

R Ullrich et al Animal Behaviour 112 (2016) 285e300 287

movements (see Fig A1) were scored using the Observersoftware

Adult zebra finch song begins with several repetitions of a singleintroductory note followed by a set of dissimilar notes The songnotes are uttered in a stereotyped sequential order that constitute alsquomotifrsquo (Fig 3) We defined a song note as a continuous morpho-logically discrete trace on a sound spectrogram Motifs that aresung in close succession result in bouts with pauses usually lastingless than 05 s Pauses longer than 2 s were considered the end ofboth a bout and a motif (Sossinka amp Beuroohner 1980) The number ofmotifs analysed per bird ranged from 93 to 324 (mean plusmn -SD frac14 1781 plusmn 7562) Between songs birds utter a number ofdifferent calls that are temporally less stereotypically deliveredthan song

Based on the audio track we divided experiments into lsquosongsegmentsrsquo and lsquononsong segmentsrsquo (Fig 3c) We defined as lsquosongsegmentrsquo the period comprising the first 2 s before the first motifnote the motif and the 2 s following the last motif note The restof the experimental 5 min were scored as lsquononsong segmentrsquo(Fig 3a) Within the lsquosong segmentrsquo we distinguished threesubdivisions (Fig 3b and c) (1) start (of a song bout 2 s beforethe onset of the first introductory note to the end of the firstmotif note or of a within-bout motif from the onset of occa-sional introductory notes to the end of the first motif note) (2)centre (including all other notes from the end of the first motifnote to the onset of the last) (3) end (the final segment of themotif from the onset of the last (not necessarily canonical) noteand up to 2 s following it less than 2 s if followed closely byanother motif) Half of the intervals between two motifs within about were considered part of the lsquostartrsquo segment and the otherhalf to be part of the lsquoendrsquo segment Because lsquostartrsquo lsquocentrersquo andlsquoendrsquo differed in duration we report the number of movementsper second (Fig 3b and c)

Among the various courtship dance-associated movementssuch as the inflation of the gular sac stereotypic head movementsupright and lower body posture we focused on three visuallysalient ones with large head and body displacements beak wipes(BW) turn-arounds (TA) and hops (Fig A1 Supplementary VideosS1 and S2) Morris (1957 p 4) wrote that a beak wipe lsquoconsists of(a) twist body (b) lower and rotate head (c) scrape [beak] (d) raisehead and (e) twist bodyrsquo Beak wipes vary in completeness fromslight nods or bows to double wiping of the beak (Morris 1957 p9 Zann 1996 p 170) Although Morris distinguished lsquodisplace-ment beak wipesrsquo (incomplete shorter duration) from lsquoautoch-thonousrsquo (complete longer duration) ones he does not score themas two qualitatively different movements but sees a close rela-tionship between them (Morris 1954 pp 307e311) We followedthe judgement when we compared the durations of beak wipesduring song and nonsong and consequently pooled all manifes-tations of the movement Morris also described turn-arounds lsquoAsthe male advances towards the female down the branch it swingsits body from side to side turning first to the left and then to theright changing the position of its feet as it does sorsquo (Morris 1954 p285) During this manoeuvre the male twists his head and tailtowards the female (Barclay et al 1992) Analogous to gestureanalysis in human communication (McNeil 1992 p 131) wesubdivided the BW movement into a preparation phase (loweringthe head) stroke (scraping the beak on the perch or wiping aboverespectively) and poststroke phase (lifting the head) and quanti-fied occurrences and durations Likewise TA movements weredivided into preparation (beginning of the turn) stroke (both feetdisplaced from the perch) and post stroke phase (completion ofthe turn) Hop movements were scored for the 10 birds of set-up Cas events counting the video frame when both feet were in the airabove the perch as the stroke of the hop and used this as the timepoint for hop quantification (Fig A1) Video scorings were made

i i i

Am

pli

tud

e(d

B)

Freq

uen

cy(k

Hz)

(a)

(b)

(c)+(2 s) +(2 s)

F L F L

02 04 06 08 1 12 14 16 18 2 22 24 26 28

Song Song

Start StartCentre CentreEnd End

SongNonsong Nonsong Nonsong

15

10

5

Time (s)

Figure 3 Schematic depiction of audio scoring (a) The 5 min that males were recorded included song (dark grey boxes) and nonsong (white boxes) segments (b) Waveform and (c)spectrogram of one bout frommale 3641 We defined song segments as the time span comprising song and the 2 s immediately before and after (indicated by light grey bars in (a))A song was defined as lasting from the start of the first introductory note (i) containing one or more motifs (outlined by red hatched lines in (c)) to 2 s after the last note of asuccession of motifs Motifs are a stereotyped recurring sequence of notes first (F) and last (L) notes of motifs are indicated by red overlay Consecutive motifs were considered tobelong to the same bout if they were separated by less than 2 s of silence or call notes (c) The dark grey bar between (b) and (c) illustrates the definition of lsquostartrsquo lsquocentrersquo and lsquoendrsquoof songs The lsquostartrsquo of a bout was defined as lasting from 2 s before the first introductory note to the end of the first motif note F (light grey bar) For consecutive motifs the lsquostartrsquoincluded half of the interval between successive motifs and the duration of the last note (L) of the preceding motif The lsquoendrsquo of a bout or motif was respectively defined as the lastnote (L) and half of the succeeding interval before the end of the first note of the following motif We extracted the time stamps (indicated by downward pointing arrows in (c)) ofthe beginning and end of introductory notes (i) first notes (F) and last notes (L) permitting calculation of note duration and of the duration of lsquostartrsquo lsquocentrersquo and lsquoendrsquo segments

R Ullrich et al Animal Behaviour 112 (2016) 285e300288

blind with respect to song behaviour eg without listening to thesound track

To analyse whether hopping coincided with utterances wevideorecorded with a medium high-speed camera (60 fps) fromthe front of the cage during experiment C (N frac14 10) We measuredhow closely in time hops occurred to introductory notes (i) thefirst (F) and the last note (L) of a motif We also included any callsbetween bouts and calls during the lsquononsongrsquo segments as wellHops taking place more than 1 s before or after a call were notconsidered Hops occurring between notes were assigned to thenote that was closer in time lsquoCall-associatedrsquo hops fell within a225 ms time window around the time stamp of the call We chosethis time window because many hops occurred immediatelybefore during or after a call (see Fig 8c in the Results) Theaverage call length was determined empirically to be 75 ms (seeAppendix)

To assess whether a birds hop and call might coincide bychance we distributed both events randomly and compared thecoincidence of hop and call by chance with the actual observationusing Monte Carlo simulation To examine the sequential order ofBW TA and hops during song we transcribed strings of the threemovements following each other with intervals shorter than 2 s inall birds from experiment C (Nfrac1410)

Statistical analysis and figures were prepared using R (version2140 R Development Core Team 2011) plus R packages lsquonlmersquo(Pinheiro Bates DebRoy Sarkar amp R Development Core Team R2011) lsquomultcomprsquo (Hothorn Bretz amp Westfall 2008) lsquolme4rsquo(Bates Maechler amp Bolker 2012) and lsquocarrsquo (Fox amp Weisberg 2011)For analysing the allocation of BW TA and hopping in the sur-rounding of a bout we ran a linear mixed model (LMM) We testedwhether the averaged occurrences of body movements per second(dependent variable) differed between locations within bouts (ielsquostartrsquo lsquocentrersquo lsquoendrsquo) As a fixed effect we entered the location intothe model and as a random effect we added an intercept for thebirds used in the experiment as well as a by-bird random slope forthe effect of location We used Akaikes information criterion (AIC)for model comparisons (ie linear regression random slope or

intercept model or ANCOVAwith or without interaction) and usedthe model with the lowest AIC value (ie LMM random slope)LMMs were fitted using the lsquolmerrsquo function in the lsquolme4rsquo libraryThe analysis was followed by Tukeys multiple comparisons posthoc test For the remaining analysis we made use of paired t testsCorrelation analyses were performed by use of simple linearregression models which also allowed us to extract the coefficientof determination (R2) We used a chi-square test of goodness-of-fitfor the overall difference between observed and expected transi-tion ratios Differences between observed and expected ratios forindividual transition types between movements were tested byLMM with a random intercept for birds P values were obtained bylikelihood ratio tests In cases of multiple testing on the same datafalse discovery rate was controlled using the BenjaminieHochbergprocedure Results reported as significant assume a false discoveryrate of 005 Data were tested for normal distribution using theShapiro-Wilk test and cube-root transformed (see Appendix) be-forehand if the initial data were not normally distributed

Ethical Note

The study with domesticated zebra finches conforms to theASABABS guidelines for the use of animals in research as well as tothe legal requirements of the German LAGESO board (permit ZH144) During the study stress was minimized and all birds werecared for and treated appropriately in accordance with the Germanlaws for animal experiments Birds used for the recording showednormal behaviour and did not appear to suffer from their occasionalremoval from the group After the study birds were used either forother experiments or for breeding purposes

RESULTS

Courtship song and dance was elicited by allowing visual andacoustic but no physical contact between a female and the focalmale The behaviour of the male was audio and video recorded for5 min For the video analysis we divided beakwipe (BW) and turn-

R Ullrich et al Animal Behaviour 112 (2016) 285e300 289

around movements (TA) into a preparation phase stroke andpoststroke phase (Fig A1) Hop movements were scored as pointevents (Fig A1) To investigate whether hops BW and TA werecoordinated with song we quantified occurrences and timing ofthese movements both during song and nonsong segments(Fig 3)

Body Movements were Associated with Song

All three body movements occurred significantly more often persecond during song than nonsong (Fig 4aec) Interestingly birdsinitiated and ended song motifs significantly more often with BWTA and hops than in the lsquocentrersquo of motifs (Fig 4def for definitionof motif divisions see Methods Fig 3) Also BW and hops but notTA were more numerous at the lsquostartrsquo than at the lsquoendrsquo of motifs(Fig 4def) These findings were consistent with coordination be-tween song and dance

During Song BW but not TA were Performed Faster

If body movements were coordinated with song they might beperformed at different durations during singing and nonsinging Toassess this we compared the durations of BW and TA in the two

(a) (b)

(d) (e)

0

02

04

06

08

0

02

04

06

08

Song Nonsong Song

N = 20 N = 20BW

0

05

1

15

08

06

04

02

0Start EndCentre Start C

Nu

mbe

r of

occ

urr

ence

ss

Figure 4 (aec) Number of body movementss during song and nonsong segments Box ploabove median) outermost values within the range of 15 times the respective quartiles (whisversus nonsong t19 frac14 455 P lt 001 (b) TA song versus nonsong t19 frac14 42 P lt 001 (c) hopsthe lsquostartrsquo lsquocentrersquo and lsquoendrsquo of song motifs Grey points represent the birds average of occurrdepict the groups average (d) Linear mixed model (LMM) lsquocentrersquo versus lsquostartrsquo estimSE frac14 0049 z frac14 294 P frac14 0009 lsquoendrsquo versus lsquocentrersquo estimate frac14 029 SE frac14 0058 z frac14 50P frac14 0003 lsquoendrsquo versus lsquostartrsquo estimate frac14 0012 SE frac14 0039 z frac14 031 P frac14 094 lsquoendrsquo versusestimate frac14 016 SE frac14 006 z frac14 278 P frac14 0014 lsquocentrersquo versus lsquostartrsquo estimate frac14 039 SE frac14P lt 0001

conditions Indeed BW were performed roughly 20 (111 ms)faster during singing whereas the duration of TA did not differ(Fig 5) Detailed frame-by-frame analysis revealed that the shorterBW duration during song was due to a faster stroke phase of theBW while preparation and poststroke phases lasted comparableamounts of time during song and during silence This suggests thatbirds can modulate the duration of BW during song facilitatingintegration of song and body movements

BW and TA were Correlated with Amount of Song

To further pursue whether song and body movements are co-ordinated we analysed individual birds Indeed the more motifs amale sang the more BW and TA he performed (Fig 6a and b) Incontrast the number of hops was not correlated with the amountof singing (Fig 6c) even though hops occurred significantly moreoften during song than nonsong (Fig 4c) Comparing the numberof movements to the number of bouts sung by each bird yieldedvery similar results (Pearson product moment correlation BWversus bout t18 frac14 245 P frac14 0025 TA versus bout t18 frac14 299P frac14 00077 hop versus bout t8 frac14 0098 P frac14 092 Fig A2) ThusBW and TA appear to be more directly associated with song thanhops

(c)

(f)

0

02

04

06

08

Nonsong Song Nonsong

N = 10TA Hop

08

1

06

04

02

0Endentre Start EndCentre

ts show median (black horizontal line) 25 and 75 quartiles (box segment below orkers) and outliers (points) P lt 005 P lt 001 P lt 0001 Paired t test (a) BW songsong versus nonsong t9 frac14 514 P lt 0001 Number of (d) BW (e) TA and (f) hops duringences in all videos Grey lines connect data of the same individual Black horizontal barsate frac14 043 SE frac14 0058 z frac14 743 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 0141 P lt 0001 (e) LMM lsquocentrersquo versus lsquostartrsquo estimate frac14 014 SE frac14 0042 z frac14 324lsquocentrersquo estimate frac14 015 SE frac14 005 z frac14 271 P frac14 0018 (f) LMM lsquoendrsquo versus lsquocentrersquo008 z frac14 496 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 024 SE frac14 005 z frac14 452

N = 20 N = 17

02

03

04

05

06

07

08M

ean

du

rati

on (

s)

Song Nonsong Song Nonsong

BW TA

Figure 5 Duration of BW and TA movements during song and nonsong For each birdthe average duration of BW (Nfrac1420 birds) and TA (Nfrac1417 birds) were calculatedP lt 0001 Paired t test BW t19 frac14 615 P lt 0001 TA t16 frac14 133 P frac14 020) Forbox plot specifications see legend to Fig 4

R Ullrich et al Animal Behaviour 112 (2016) 285e300290

Hop Rates During Song Correlated with those Outside Song

Individuals varied considerably in frequency of BW TA and hopsduring song We wondered whether an individuals propensity toperform more or less song-associated movements was related tohow often these movements occurred when they were not singingInterestingly the numbers of hops (Fig A3c) during song andnonsong were significantly correlated whereas this was not thecase for BW (Fig A3a) and TA (Fig A3b)

During Song Numbers of BW and TA were Tightly Related

Given that all three movements occurred more frequentlywith song than outside the song context (Fig 4aec) we checkedwhether all three movements are part of an integrated songchoreography Consistent with this notion during song but notoutside the song context the number of BW and TA were morerelated to each other than TA were with hops or BW with hops(Fig 7aec Pearson product moment correlation song TA versusBW t18 frac14 204 P frac14 0056 TA versus hop t8 frac14 016 P frac14 088 BWversus hop t8 frac14 017 P frac14 087 nonsong BW versus TAt18 frac14 008 P frac14 093 hop versus TA t8 frac14 116 P frac14 028 9 hopversus BW t8 frac14 038 P frac14 071) This finding together with theresults shown in Fig 6 raised the possibility that BW and TA area more tightly integrated part of the song choreography thanhops

Hops Coincided with Particular Notes

To determine whether hops were in fact less coordinated withsong than BW and TA we quantified when hops occurred inrelationship to song using frame by frame video analysis Because

hopping behaviour is often accompanied by calls (Moorman ampBolhuis 2013 p 112 Zann 1996 p 197) we measured the in-terval between a hop and the introductory the first and the lastmotif notes We found that most hops coincided exactly orclosely in time with the utterance of a note or call This wasparticularly striking for the introductory notes (Fig 8a) Notehowever that hops and vocalizations were not obligatorilycoupled

Might the striking coincidence of hops and introductory notesstem from physical constraints of hopping such as a minimuminterval between hops mandated by movement mechanics Toanswer this question we analysed how the intervals between twohops were distributed Only two hop intervals out of 588 wereshorter than 200 ms probably reflecting the limit of how fast twosuccessive hops can be performed During song 49 of all interhopintervals ranged between 200 and 1000 ms (Fig 8b) Interhop in-tervals of this range of durations were between 200 and 400 mslong Hops of this duration were almost twice as numerous duringsong than during nonsong (24 versus 13) Although birds per-formed a very wide range of interhop intervals during song (seerightmost columns Fig 8b) we observed 24 of them within thesame time span as interintroductory note intervals (mean plusmn -SD frac14 255 plusmn 215 ms) Although in both contexts hop intervals be-tween 200 and 400 msweremost frequent the high coincidence ofhops with introductory notes therefore does not appear to be asimple by-product of a narrow range of hop interval durationsmandated by physical constraints (Fig 8a) Instead it is consistentwith the possibility that hops and notes coincide as a consequenceof voluntary control

Were hops and calls also associated when zebra finches werenot singing We analysed the duration between a hop and the callclosest in time and found that 56 of all hopping behaviour clus-tered in a 2 s timewindowaround calls (ie1 s before plus 1 s after)Twenty per cent of all hops were directly associated with calls(Fig 8c and see the Appendix) We ruled out the possibility that theclose association of hops and calls was a function of two indepen-dent events being associated coincidentally hops and calls weresignificantly more often linked in time than would be expected bychance (Fig 8d hop estimated versus observed one-tailed paired ttest t9 frac14 314 P lt 001)

Behaviour Transition Ratios Differed from those Expected

To analyse the sequence of movements we transcribed theorder of transitions between BW TA and hops following eachother with intervals shorter than 2 s Longer intervals wereconsidered the start and end of a transition string Fig 9 shows thesequence diagram of movement transition probabilities across all10 birds from experiment C during bouts Transition probabilitiesthat would be expected if the three movements were equallylikely to follow each other were calculated based on the observednumber of movements and transition strings (see Appendix fordetails) Observed probabilities of all transition types in theirentirety differed significantly from the expected values(c2

14 frac14 11678 P lt 0001) Transitions from TA to TA (LMMc2

1 frac141192 P frac14 00005 difference frac14 011 plusmn 002 SE) and fromhop to TA (LMM c2

1 frac14864 P frac14 00033 difference frac14 007 plusmn 002SE) occurred significantly less frequently than expected by chancewhile transitions from hop to hop were significantly morefrequent (LMM c2

1 frac141072 P frac14 0001 difference frac14 thorn015 plusmn 003SE see also Figs A4 and A5)

In individual birds transition string length varied between 2and 17 movements Not all possible movement combinations

P = 0014

R2 = 0293

R2 = 031

R2 = 0076

N = 20

N = 10

N = 20

300

100

150

100

50

90

80

70

60

50

40

30

100 150 250 300 350

0

No of motifs

No

of

hop

sN

o o

f TA

(a)

(b)

(c)

400

No

of

BW

200

P = 0011

P = 044

200

Figure 6 Number of (a) BW (b) TA and (c) hops in relation to number of motifs sungPearson product moment correlation BW versus motif t18 frac14 27 P lt 005 TA versusmotif t18 frac14 284 P lt 005 hop versus motif t8 frac14 081 P frac14 044

R Ullrich et al Animal Behaviour 112 (2016) 285e300 291

occurred and some were particularly frequent (Table A2) Consis-tent with our hypothesis that sequences of movements during songare part of a choreography the frequency distribution of stringlength was skewed towards longer strings during song than duringnonsong (Fig A6)

Finally we examined whether age (and by inference experi-ence) correlatedwith dance vigourWe analysed the number of BWTA and hops in relation to age but did not find a systematic asso-ciation as reported before (Williams 2001 Pearson productmoment correlation age versus BW t18 frac14 014 P frac14 088 ageversus TA t18 frac14 15 P frac14 015 age versus hop t8 frac14 084P frac14 043)

DISCUSSION

Here we comprehensively show for the first time multipleways in which the expression of dance is strongly but not oblig-atorily associated with the expression of song in zebra finchesStereotypic movements that is BW TA and hops occurredsignificantly more during song than during silence All threemovements clustered at the start and end of motifs and hopscoincided with notes particularly the introductory but also thefirst and last motif notes BW were performed faster during songthan during silence but TA were not The more birds sang themore BW and TA occurred Dance sequences were flexibly but notrandomly arranged Together these results suggest a choreogra-phy of song and dance that signals courtship intensity A previousstudy (Williams 2001) did not find a strongly patterned associa-tion between song and dance movements which might bebecause hops forward left right back up and down headmovements were pooled However Williams (2001 p 3505)observed qualitatively that lsquothe relatively infrequent dancemovements appear to be initiated at a number of specific lsquohotspotsrsquo within the songrsquo

Clustering of BW TA and hops at the beginning and end ofmotifs may serve as lsquoinitiation and closurersquo signals The male coulddraw attention to his courtship before the relatively quiet songbecomes audible to the receivers The repeated 180 turning of thebird while singing as he approaches the female is associated with aregular change in song sound amplitude This could also allow herto discriminate the courting males sound pattern from the noisyenvironment of the vocalizing flock mates and provide an exampleof lsquospatial release from maskingrsquo (Bee amp Micheyl 2008) Gesturessuch as BW and TA at the beginning and end of motifs might alsofocus the females attention on the motif structure and thus aid inthe evaluation of song stereotypy a feature relevant for femalechoice (Riebel 2009) When analysing the location of movementswithin the motif we did not distinguish the very first and last fromthe other motifs of a bout However the number of movements abird performed correlated with both the motif and bout count to avery similar degree suggesting that the placement of bodymovements is not primarily tied to the beginning or end of a songbout

Courtship intensity in zebra finch males is influenced by thesocial background (Ruploh Bischof amp Engelhardt 2012) the sizeof the experimental cage the experimental procedure itself(Immelmann 1959 p 447) dopamine turnover in brain areascontrolling the motor patterning of song (Rauceo et al 2008) andthe females reaction (Zann 1996 pp 171e173) As we useddifferent cage sizes and experimental set-ups our resultsencompass this variability yet particular movements wereconsistently and significantly associated with courtship song Avigorously courting male sings more motifs per unit time (Riebel2009) and we show that the number of song motifs in individualmales also strongly predicts their BW and TA activity Moreover

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

30 fps 30 fps

60 fps

25 fps

(a)

(b)

(c)

Figure 2 Experimental set-up for (a) experiment A (b) experiment B and (c) experiment C For experiments A and C males and females occupied two separate plastic-walled cages(51 30 cm and 40 cm high) separated by a removable opaque divider The top of the cage and one of the long sides consisted of transparent plastic material Videos were recordedfrom above and additionally from the front (experiment C) audio was recorded from the side through an opening of the cage For experiment B cages (40 30 cm and 40 cm high)were connected by a 15 m long tunnel (150 20 cm and 30 cm high) containing a single long perch The front of the tunnel consisted of transparent plastic material the other sidesof metal wire mesh Video was taped from the front audio from above The male entered the tunnel at the start of the 5 min test period after an opaque divider was removed Themale and female heard each other in all set-ups but could only see each other through a 17 17 cm wire mesh (experiment A B) or transparent plastic window (experiment C)during the 5 min test period Birds could approach each other to a vicinity of 5 cm but not interact physically During indoor experiments (A C) the cage was illuminated by fourfluorescent lamps (18 W) experiments outdoors (B) were performed under ambient light

R Ullrich et al Animal Behaviour 112 (2016) 285e300 287

movements (see Fig A1) were scored using the Observersoftware

Adult zebra finch song begins with several repetitions of a singleintroductory note followed by a set of dissimilar notes The songnotes are uttered in a stereotyped sequential order that constitute alsquomotifrsquo (Fig 3) We defined a song note as a continuous morpho-logically discrete trace on a sound spectrogram Motifs that aresung in close succession result in bouts with pauses usually lastingless than 05 s Pauses longer than 2 s were considered the end ofboth a bout and a motif (Sossinka amp Beuroohner 1980) The number ofmotifs analysed per bird ranged from 93 to 324 (mean plusmn -SD frac14 1781 plusmn 7562) Between songs birds utter a number ofdifferent calls that are temporally less stereotypically deliveredthan song

Based on the audio track we divided experiments into lsquosongsegmentsrsquo and lsquononsong segmentsrsquo (Fig 3c) We defined as lsquosongsegmentrsquo the period comprising the first 2 s before the first motifnote the motif and the 2 s following the last motif note The restof the experimental 5 min were scored as lsquononsong segmentrsquo(Fig 3a) Within the lsquosong segmentrsquo we distinguished threesubdivisions (Fig 3b and c) (1) start (of a song bout 2 s beforethe onset of the first introductory note to the end of the firstmotif note or of a within-bout motif from the onset of occa-sional introductory notes to the end of the first motif note) (2)centre (including all other notes from the end of the first motifnote to the onset of the last) (3) end (the final segment of themotif from the onset of the last (not necessarily canonical) noteand up to 2 s following it less than 2 s if followed closely byanother motif) Half of the intervals between two motifs within about were considered part of the lsquostartrsquo segment and the otherhalf to be part of the lsquoendrsquo segment Because lsquostartrsquo lsquocentrersquo andlsquoendrsquo differed in duration we report the number of movementsper second (Fig 3b and c)

Among the various courtship dance-associated movementssuch as the inflation of the gular sac stereotypic head movementsupright and lower body posture we focused on three visuallysalient ones with large head and body displacements beak wipes(BW) turn-arounds (TA) and hops (Fig A1 Supplementary VideosS1 and S2) Morris (1957 p 4) wrote that a beak wipe lsquoconsists of(a) twist body (b) lower and rotate head (c) scrape [beak] (d) raisehead and (e) twist bodyrsquo Beak wipes vary in completeness fromslight nods or bows to double wiping of the beak (Morris 1957 p9 Zann 1996 p 170) Although Morris distinguished lsquodisplace-ment beak wipesrsquo (incomplete shorter duration) from lsquoautoch-thonousrsquo (complete longer duration) ones he does not score themas two qualitatively different movements but sees a close rela-tionship between them (Morris 1954 pp 307e311) We followedthe judgement when we compared the durations of beak wipesduring song and nonsong and consequently pooled all manifes-tations of the movement Morris also described turn-arounds lsquoAsthe male advances towards the female down the branch it swingsits body from side to side turning first to the left and then to theright changing the position of its feet as it does sorsquo (Morris 1954 p285) During this manoeuvre the male twists his head and tailtowards the female (Barclay et al 1992) Analogous to gestureanalysis in human communication (McNeil 1992 p 131) wesubdivided the BW movement into a preparation phase (loweringthe head) stroke (scraping the beak on the perch or wiping aboverespectively) and poststroke phase (lifting the head) and quanti-fied occurrences and durations Likewise TA movements weredivided into preparation (beginning of the turn) stroke (both feetdisplaced from the perch) and post stroke phase (completion ofthe turn) Hop movements were scored for the 10 birds of set-up Cas events counting the video frame when both feet were in the airabove the perch as the stroke of the hop and used this as the timepoint for hop quantification (Fig A1) Video scorings were made

i i i

Am

pli

tud

e(d

B)

Freq

uen

cy(k

Hz)

(a)

(b)

(c)+(2 s) +(2 s)

F L F L

02 04 06 08 1 12 14 16 18 2 22 24 26 28

Song Song

Start StartCentre CentreEnd End

SongNonsong Nonsong Nonsong

15

10

5

Time (s)

Figure 3 Schematic depiction of audio scoring (a) The 5 min that males were recorded included song (dark grey boxes) and nonsong (white boxes) segments (b) Waveform and (c)spectrogram of one bout frommale 3641 We defined song segments as the time span comprising song and the 2 s immediately before and after (indicated by light grey bars in (a))A song was defined as lasting from the start of the first introductory note (i) containing one or more motifs (outlined by red hatched lines in (c)) to 2 s after the last note of asuccession of motifs Motifs are a stereotyped recurring sequence of notes first (F) and last (L) notes of motifs are indicated by red overlay Consecutive motifs were considered tobelong to the same bout if they were separated by less than 2 s of silence or call notes (c) The dark grey bar between (b) and (c) illustrates the definition of lsquostartrsquo lsquocentrersquo and lsquoendrsquoof songs The lsquostartrsquo of a bout was defined as lasting from 2 s before the first introductory note to the end of the first motif note F (light grey bar) For consecutive motifs the lsquostartrsquoincluded half of the interval between successive motifs and the duration of the last note (L) of the preceding motif The lsquoendrsquo of a bout or motif was respectively defined as the lastnote (L) and half of the succeeding interval before the end of the first note of the following motif We extracted the time stamps (indicated by downward pointing arrows in (c)) ofthe beginning and end of introductory notes (i) first notes (F) and last notes (L) permitting calculation of note duration and of the duration of lsquostartrsquo lsquocentrersquo and lsquoendrsquo segments

R Ullrich et al Animal Behaviour 112 (2016) 285e300288

blind with respect to song behaviour eg without listening to thesound track

To analyse whether hopping coincided with utterances wevideorecorded with a medium high-speed camera (60 fps) fromthe front of the cage during experiment C (N frac14 10) We measuredhow closely in time hops occurred to introductory notes (i) thefirst (F) and the last note (L) of a motif We also included any callsbetween bouts and calls during the lsquononsongrsquo segments as wellHops taking place more than 1 s before or after a call were notconsidered Hops occurring between notes were assigned to thenote that was closer in time lsquoCall-associatedrsquo hops fell within a225 ms time window around the time stamp of the call We chosethis time window because many hops occurred immediatelybefore during or after a call (see Fig 8c in the Results) Theaverage call length was determined empirically to be 75 ms (seeAppendix)

To assess whether a birds hop and call might coincide bychance we distributed both events randomly and compared thecoincidence of hop and call by chance with the actual observationusing Monte Carlo simulation To examine the sequential order ofBW TA and hops during song we transcribed strings of the threemovements following each other with intervals shorter than 2 s inall birds from experiment C (Nfrac1410)

Statistical analysis and figures were prepared using R (version2140 R Development Core Team 2011) plus R packages lsquonlmersquo(Pinheiro Bates DebRoy Sarkar amp R Development Core Team R2011) lsquomultcomprsquo (Hothorn Bretz amp Westfall 2008) lsquolme4rsquo(Bates Maechler amp Bolker 2012) and lsquocarrsquo (Fox amp Weisberg 2011)For analysing the allocation of BW TA and hopping in the sur-rounding of a bout we ran a linear mixed model (LMM) We testedwhether the averaged occurrences of body movements per second(dependent variable) differed between locations within bouts (ielsquostartrsquo lsquocentrersquo lsquoendrsquo) As a fixed effect we entered the location intothe model and as a random effect we added an intercept for thebirds used in the experiment as well as a by-bird random slope forthe effect of location We used Akaikes information criterion (AIC)for model comparisons (ie linear regression random slope or

intercept model or ANCOVAwith or without interaction) and usedthe model with the lowest AIC value (ie LMM random slope)LMMs were fitted using the lsquolmerrsquo function in the lsquolme4rsquo libraryThe analysis was followed by Tukeys multiple comparisons posthoc test For the remaining analysis we made use of paired t testsCorrelation analyses were performed by use of simple linearregression models which also allowed us to extract the coefficientof determination (R2) We used a chi-square test of goodness-of-fitfor the overall difference between observed and expected transi-tion ratios Differences between observed and expected ratios forindividual transition types between movements were tested byLMM with a random intercept for birds P values were obtained bylikelihood ratio tests In cases of multiple testing on the same datafalse discovery rate was controlled using the BenjaminieHochbergprocedure Results reported as significant assume a false discoveryrate of 005 Data were tested for normal distribution using theShapiro-Wilk test and cube-root transformed (see Appendix) be-forehand if the initial data were not normally distributed

Ethical Note

The study with domesticated zebra finches conforms to theASABABS guidelines for the use of animals in research as well as tothe legal requirements of the German LAGESO board (permit ZH144) During the study stress was minimized and all birds werecared for and treated appropriately in accordance with the Germanlaws for animal experiments Birds used for the recording showednormal behaviour and did not appear to suffer from their occasionalremoval from the group After the study birds were used either forother experiments or for breeding purposes

RESULTS

Courtship song and dance was elicited by allowing visual andacoustic but no physical contact between a female and the focalmale The behaviour of the male was audio and video recorded for5 min For the video analysis we divided beakwipe (BW) and turn-

R Ullrich et al Animal Behaviour 112 (2016) 285e300 289

around movements (TA) into a preparation phase stroke andpoststroke phase (Fig A1) Hop movements were scored as pointevents (Fig A1) To investigate whether hops BW and TA werecoordinated with song we quantified occurrences and timing ofthese movements both during song and nonsong segments(Fig 3)

Body Movements were Associated with Song

All three body movements occurred significantly more often persecond during song than nonsong (Fig 4aec) Interestingly birdsinitiated and ended song motifs significantly more often with BWTA and hops than in the lsquocentrersquo of motifs (Fig 4def for definitionof motif divisions see Methods Fig 3) Also BW and hops but notTA were more numerous at the lsquostartrsquo than at the lsquoendrsquo of motifs(Fig 4def) These findings were consistent with coordination be-tween song and dance

During Song BW but not TA were Performed Faster

If body movements were coordinated with song they might beperformed at different durations during singing and nonsinging Toassess this we compared the durations of BW and TA in the two

(a) (b)

(d) (e)

0

02

04

06

08

0

02

04

06

08

Song Nonsong Song

N = 20 N = 20BW

0

05

1

15

08

06

04

02

0Start EndCentre Start C

Nu

mbe

r of

occ

urr

ence

ss

Figure 4 (aec) Number of body movementss during song and nonsong segments Box ploabove median) outermost values within the range of 15 times the respective quartiles (whisversus nonsong t19 frac14 455 P lt 001 (b) TA song versus nonsong t19 frac14 42 P lt 001 (c) hopsthe lsquostartrsquo lsquocentrersquo and lsquoendrsquo of song motifs Grey points represent the birds average of occurrdepict the groups average (d) Linear mixed model (LMM) lsquocentrersquo versus lsquostartrsquo estimSE frac14 0049 z frac14 294 P frac14 0009 lsquoendrsquo versus lsquocentrersquo estimate frac14 029 SE frac14 0058 z frac14 50P frac14 0003 lsquoendrsquo versus lsquostartrsquo estimate frac14 0012 SE frac14 0039 z frac14 031 P frac14 094 lsquoendrsquo versusestimate frac14 016 SE frac14 006 z frac14 278 P frac14 0014 lsquocentrersquo versus lsquostartrsquo estimate frac14 039 SE frac14P lt 0001

conditions Indeed BW were performed roughly 20 (111 ms)faster during singing whereas the duration of TA did not differ(Fig 5) Detailed frame-by-frame analysis revealed that the shorterBW duration during song was due to a faster stroke phase of theBW while preparation and poststroke phases lasted comparableamounts of time during song and during silence This suggests thatbirds can modulate the duration of BW during song facilitatingintegration of song and body movements

BW and TA were Correlated with Amount of Song

To further pursue whether song and body movements are co-ordinated we analysed individual birds Indeed the more motifs amale sang the more BW and TA he performed (Fig 6a and b) Incontrast the number of hops was not correlated with the amountof singing (Fig 6c) even though hops occurred significantly moreoften during song than nonsong (Fig 4c) Comparing the numberof movements to the number of bouts sung by each bird yieldedvery similar results (Pearson product moment correlation BWversus bout t18 frac14 245 P frac14 0025 TA versus bout t18 frac14 299P frac14 00077 hop versus bout t8 frac14 0098 P frac14 092 Fig A2) ThusBW and TA appear to be more directly associated with song thanhops

(c)

(f)

0

02

04

06

08

Nonsong Song Nonsong

N = 10TA Hop

08

1

06

04

02

0Endentre Start EndCentre

ts show median (black horizontal line) 25 and 75 quartiles (box segment below orkers) and outliers (points) P lt 005 P lt 001 P lt 0001 Paired t test (a) BW songsong versus nonsong t9 frac14 514 P lt 0001 Number of (d) BW (e) TA and (f) hops duringences in all videos Grey lines connect data of the same individual Black horizontal barsate frac14 043 SE frac14 0058 z frac14 743 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 0141 P lt 0001 (e) LMM lsquocentrersquo versus lsquostartrsquo estimate frac14 014 SE frac14 0042 z frac14 324lsquocentrersquo estimate frac14 015 SE frac14 005 z frac14 271 P frac14 0018 (f) LMM lsquoendrsquo versus lsquocentrersquo008 z frac14 496 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 024 SE frac14 005 z frac14 452

N = 20 N = 17

02

03

04

05

06

07

08M

ean

du

rati

on (

s)

Song Nonsong Song Nonsong

BW TA

Figure 5 Duration of BW and TA movements during song and nonsong For each birdthe average duration of BW (Nfrac1420 birds) and TA (Nfrac1417 birds) were calculatedP lt 0001 Paired t test BW t19 frac14 615 P lt 0001 TA t16 frac14 133 P frac14 020) Forbox plot specifications see legend to Fig 4

R Ullrich et al Animal Behaviour 112 (2016) 285e300290

Hop Rates During Song Correlated with those Outside Song

Individuals varied considerably in frequency of BW TA and hopsduring song We wondered whether an individuals propensity toperform more or less song-associated movements was related tohow often these movements occurred when they were not singingInterestingly the numbers of hops (Fig A3c) during song andnonsong were significantly correlated whereas this was not thecase for BW (Fig A3a) and TA (Fig A3b)

During Song Numbers of BW and TA were Tightly Related

Given that all three movements occurred more frequentlywith song than outside the song context (Fig 4aec) we checkedwhether all three movements are part of an integrated songchoreography Consistent with this notion during song but notoutside the song context the number of BW and TA were morerelated to each other than TA were with hops or BW with hops(Fig 7aec Pearson product moment correlation song TA versusBW t18 frac14 204 P frac14 0056 TA versus hop t8 frac14 016 P frac14 088 BWversus hop t8 frac14 017 P frac14 087 nonsong BW versus TAt18 frac14 008 P frac14 093 hop versus TA t8 frac14 116 P frac14 028 9 hopversus BW t8 frac14 038 P frac14 071) This finding together with theresults shown in Fig 6 raised the possibility that BW and TA area more tightly integrated part of the song choreography thanhops

Hops Coincided with Particular Notes

To determine whether hops were in fact less coordinated withsong than BW and TA we quantified when hops occurred inrelationship to song using frame by frame video analysis Because

hopping behaviour is often accompanied by calls (Moorman ampBolhuis 2013 p 112 Zann 1996 p 197) we measured the in-terval between a hop and the introductory the first and the lastmotif notes We found that most hops coincided exactly orclosely in time with the utterance of a note or call This wasparticularly striking for the introductory notes (Fig 8a) Notehowever that hops and vocalizations were not obligatorilycoupled

Might the striking coincidence of hops and introductory notesstem from physical constraints of hopping such as a minimuminterval between hops mandated by movement mechanics Toanswer this question we analysed how the intervals between twohops were distributed Only two hop intervals out of 588 wereshorter than 200 ms probably reflecting the limit of how fast twosuccessive hops can be performed During song 49 of all interhopintervals ranged between 200 and 1000 ms (Fig 8b) Interhop in-tervals of this range of durations were between 200 and 400 mslong Hops of this duration were almost twice as numerous duringsong than during nonsong (24 versus 13) Although birds per-formed a very wide range of interhop intervals during song (seerightmost columns Fig 8b) we observed 24 of them within thesame time span as interintroductory note intervals (mean plusmn -SD frac14 255 plusmn 215 ms) Although in both contexts hop intervals be-tween 200 and 400 msweremost frequent the high coincidence ofhops with introductory notes therefore does not appear to be asimple by-product of a narrow range of hop interval durationsmandated by physical constraints (Fig 8a) Instead it is consistentwith the possibility that hops and notes coincide as a consequenceof voluntary control

Were hops and calls also associated when zebra finches werenot singing We analysed the duration between a hop and the callclosest in time and found that 56 of all hopping behaviour clus-tered in a 2 s timewindowaround calls (ie1 s before plus 1 s after)Twenty per cent of all hops were directly associated with calls(Fig 8c and see the Appendix) We ruled out the possibility that theclose association of hops and calls was a function of two indepen-dent events being associated coincidentally hops and calls weresignificantly more often linked in time than would be expected bychance (Fig 8d hop estimated versus observed one-tailed paired ttest t9 frac14 314 P lt 001)

Behaviour Transition Ratios Differed from those Expected

To analyse the sequence of movements we transcribed theorder of transitions between BW TA and hops following eachother with intervals shorter than 2 s Longer intervals wereconsidered the start and end of a transition string Fig 9 shows thesequence diagram of movement transition probabilities across all10 birds from experiment C during bouts Transition probabilitiesthat would be expected if the three movements were equallylikely to follow each other were calculated based on the observednumber of movements and transition strings (see Appendix fordetails) Observed probabilities of all transition types in theirentirety differed significantly from the expected values(c2

14 frac14 11678 P lt 0001) Transitions from TA to TA (LMMc2

1 frac141192 P frac14 00005 difference frac14 011 plusmn 002 SE) and fromhop to TA (LMM c2

1 frac14864 P frac14 00033 difference frac14 007 plusmn 002SE) occurred significantly less frequently than expected by chancewhile transitions from hop to hop were significantly morefrequent (LMM c2

1 frac141072 P frac14 0001 difference frac14 thorn015 plusmn 003SE see also Figs A4 and A5)

In individual birds transition string length varied between 2and 17 movements Not all possible movement combinations

P = 0014

R2 = 0293

R2 = 031

R2 = 0076

N = 20

N = 10

N = 20

300

100

150

100

50

90

80

70

60

50

40

30

100 150 250 300 350

0

No of motifs

No

of

hop

sN

o o

f TA

(a)

(b)

(c)

400

No

of

BW

200

P = 0011

P = 044

200

Figure 6 Number of (a) BW (b) TA and (c) hops in relation to number of motifs sungPearson product moment correlation BW versus motif t18 frac14 27 P lt 005 TA versusmotif t18 frac14 284 P lt 005 hop versus motif t8 frac14 081 P frac14 044

R Ullrich et al Animal Behaviour 112 (2016) 285e300 291

occurred and some were particularly frequent (Table A2) Consis-tent with our hypothesis that sequences of movements during songare part of a choreography the frequency distribution of stringlength was skewed towards longer strings during song than duringnonsong (Fig A6)

Finally we examined whether age (and by inference experi-ence) correlatedwith dance vigourWe analysed the number of BWTA and hops in relation to age but did not find a systematic asso-ciation as reported before (Williams 2001 Pearson productmoment correlation age versus BW t18 frac14 014 P frac14 088 ageversus TA t18 frac14 15 P frac14 015 age versus hop t8 frac14 084P frac14 043)

DISCUSSION

Here we comprehensively show for the first time multipleways in which the expression of dance is strongly but not oblig-atorily associated with the expression of song in zebra finchesStereotypic movements that is BW TA and hops occurredsignificantly more during song than during silence All threemovements clustered at the start and end of motifs and hopscoincided with notes particularly the introductory but also thefirst and last motif notes BW were performed faster during songthan during silence but TA were not The more birds sang themore BW and TA occurred Dance sequences were flexibly but notrandomly arranged Together these results suggest a choreogra-phy of song and dance that signals courtship intensity A previousstudy (Williams 2001) did not find a strongly patterned associa-tion between song and dance movements which might bebecause hops forward left right back up and down headmovements were pooled However Williams (2001 p 3505)observed qualitatively that lsquothe relatively infrequent dancemovements appear to be initiated at a number of specific lsquohotspotsrsquo within the songrsquo

Clustering of BW TA and hops at the beginning and end ofmotifs may serve as lsquoinitiation and closurersquo signals The male coulddraw attention to his courtship before the relatively quiet songbecomes audible to the receivers The repeated 180 turning of thebird while singing as he approaches the female is associated with aregular change in song sound amplitude This could also allow herto discriminate the courting males sound pattern from the noisyenvironment of the vocalizing flock mates and provide an exampleof lsquospatial release from maskingrsquo (Bee amp Micheyl 2008) Gesturessuch as BW and TA at the beginning and end of motifs might alsofocus the females attention on the motif structure and thus aid inthe evaluation of song stereotypy a feature relevant for femalechoice (Riebel 2009) When analysing the location of movementswithin the motif we did not distinguish the very first and last fromthe other motifs of a bout However the number of movements abird performed correlated with both the motif and bout count to avery similar degree suggesting that the placement of bodymovements is not primarily tied to the beginning or end of a songbout

Courtship intensity in zebra finch males is influenced by thesocial background (Ruploh Bischof amp Engelhardt 2012) the sizeof the experimental cage the experimental procedure itself(Immelmann 1959 p 447) dopamine turnover in brain areascontrolling the motor patterning of song (Rauceo et al 2008) andthe females reaction (Zann 1996 pp 171e173) As we useddifferent cage sizes and experimental set-ups our resultsencompass this variability yet particular movements wereconsistently and significantly associated with courtship song Avigorously courting male sings more motifs per unit time (Riebel2009) and we show that the number of song motifs in individualmales also strongly predicts their BW and TA activity Moreover

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

i i i

Am

pli

tud

e(d

B)

Freq

uen

cy(k

Hz)

(a)

(b)

(c)+(2 s) +(2 s)

F L F L

02 04 06 08 1 12 14 16 18 2 22 24 26 28

Song Song

Start StartCentre CentreEnd End

SongNonsong Nonsong Nonsong

15

10

5

Time (s)

Figure 3 Schematic depiction of audio scoring (a) The 5 min that males were recorded included song (dark grey boxes) and nonsong (white boxes) segments (b) Waveform and (c)spectrogram of one bout frommale 3641 We defined song segments as the time span comprising song and the 2 s immediately before and after (indicated by light grey bars in (a))A song was defined as lasting from the start of the first introductory note (i) containing one or more motifs (outlined by red hatched lines in (c)) to 2 s after the last note of asuccession of motifs Motifs are a stereotyped recurring sequence of notes first (F) and last (L) notes of motifs are indicated by red overlay Consecutive motifs were considered tobelong to the same bout if they were separated by less than 2 s of silence or call notes (c) The dark grey bar between (b) and (c) illustrates the definition of lsquostartrsquo lsquocentrersquo and lsquoendrsquoof songs The lsquostartrsquo of a bout was defined as lasting from 2 s before the first introductory note to the end of the first motif note F (light grey bar) For consecutive motifs the lsquostartrsquoincluded half of the interval between successive motifs and the duration of the last note (L) of the preceding motif The lsquoendrsquo of a bout or motif was respectively defined as the lastnote (L) and half of the succeeding interval before the end of the first note of the following motif We extracted the time stamps (indicated by downward pointing arrows in (c)) ofthe beginning and end of introductory notes (i) first notes (F) and last notes (L) permitting calculation of note duration and of the duration of lsquostartrsquo lsquocentrersquo and lsquoendrsquo segments

R Ullrich et al Animal Behaviour 112 (2016) 285e300288

blind with respect to song behaviour eg without listening to thesound track

To analyse whether hopping coincided with utterances wevideorecorded with a medium high-speed camera (60 fps) fromthe front of the cage during experiment C (N frac14 10) We measuredhow closely in time hops occurred to introductory notes (i) thefirst (F) and the last note (L) of a motif We also included any callsbetween bouts and calls during the lsquononsongrsquo segments as wellHops taking place more than 1 s before or after a call were notconsidered Hops occurring between notes were assigned to thenote that was closer in time lsquoCall-associatedrsquo hops fell within a225 ms time window around the time stamp of the call We chosethis time window because many hops occurred immediatelybefore during or after a call (see Fig 8c in the Results) Theaverage call length was determined empirically to be 75 ms (seeAppendix)

To assess whether a birds hop and call might coincide bychance we distributed both events randomly and compared thecoincidence of hop and call by chance with the actual observationusing Monte Carlo simulation To examine the sequential order ofBW TA and hops during song we transcribed strings of the threemovements following each other with intervals shorter than 2 s inall birds from experiment C (Nfrac1410)

Statistical analysis and figures were prepared using R (version2140 R Development Core Team 2011) plus R packages lsquonlmersquo(Pinheiro Bates DebRoy Sarkar amp R Development Core Team R2011) lsquomultcomprsquo (Hothorn Bretz amp Westfall 2008) lsquolme4rsquo(Bates Maechler amp Bolker 2012) and lsquocarrsquo (Fox amp Weisberg 2011)For analysing the allocation of BW TA and hopping in the sur-rounding of a bout we ran a linear mixed model (LMM) We testedwhether the averaged occurrences of body movements per second(dependent variable) differed between locations within bouts (ielsquostartrsquo lsquocentrersquo lsquoendrsquo) As a fixed effect we entered the location intothe model and as a random effect we added an intercept for thebirds used in the experiment as well as a by-bird random slope forthe effect of location We used Akaikes information criterion (AIC)for model comparisons (ie linear regression random slope or

intercept model or ANCOVAwith or without interaction) and usedthe model with the lowest AIC value (ie LMM random slope)LMMs were fitted using the lsquolmerrsquo function in the lsquolme4rsquo libraryThe analysis was followed by Tukeys multiple comparisons posthoc test For the remaining analysis we made use of paired t testsCorrelation analyses were performed by use of simple linearregression models which also allowed us to extract the coefficientof determination (R2) We used a chi-square test of goodness-of-fitfor the overall difference between observed and expected transi-tion ratios Differences between observed and expected ratios forindividual transition types between movements were tested byLMM with a random intercept for birds P values were obtained bylikelihood ratio tests In cases of multiple testing on the same datafalse discovery rate was controlled using the BenjaminieHochbergprocedure Results reported as significant assume a false discoveryrate of 005 Data were tested for normal distribution using theShapiro-Wilk test and cube-root transformed (see Appendix) be-forehand if the initial data were not normally distributed

Ethical Note

The study with domesticated zebra finches conforms to theASABABS guidelines for the use of animals in research as well as tothe legal requirements of the German LAGESO board (permit ZH144) During the study stress was minimized and all birds werecared for and treated appropriately in accordance with the Germanlaws for animal experiments Birds used for the recording showednormal behaviour and did not appear to suffer from their occasionalremoval from the group After the study birds were used either forother experiments or for breeding purposes

RESULTS

Courtship song and dance was elicited by allowing visual andacoustic but no physical contact between a female and the focalmale The behaviour of the male was audio and video recorded for5 min For the video analysis we divided beakwipe (BW) and turn-

R Ullrich et al Animal Behaviour 112 (2016) 285e300 289

around movements (TA) into a preparation phase stroke andpoststroke phase (Fig A1) Hop movements were scored as pointevents (Fig A1) To investigate whether hops BW and TA werecoordinated with song we quantified occurrences and timing ofthese movements both during song and nonsong segments(Fig 3)

Body Movements were Associated with Song

All three body movements occurred significantly more often persecond during song than nonsong (Fig 4aec) Interestingly birdsinitiated and ended song motifs significantly more often with BWTA and hops than in the lsquocentrersquo of motifs (Fig 4def for definitionof motif divisions see Methods Fig 3) Also BW and hops but notTA were more numerous at the lsquostartrsquo than at the lsquoendrsquo of motifs(Fig 4def) These findings were consistent with coordination be-tween song and dance

During Song BW but not TA were Performed Faster

If body movements were coordinated with song they might beperformed at different durations during singing and nonsinging Toassess this we compared the durations of BW and TA in the two

(a) (b)

(d) (e)

0

02

04

06

08

0

02

04

06

08

Song Nonsong Song

N = 20 N = 20BW

0

05

1

15

08

06

04

02

0Start EndCentre Start C

Nu

mbe

r of

occ

urr

ence

ss

Figure 4 (aec) Number of body movementss during song and nonsong segments Box ploabove median) outermost values within the range of 15 times the respective quartiles (whisversus nonsong t19 frac14 455 P lt 001 (b) TA song versus nonsong t19 frac14 42 P lt 001 (c) hopsthe lsquostartrsquo lsquocentrersquo and lsquoendrsquo of song motifs Grey points represent the birds average of occurrdepict the groups average (d) Linear mixed model (LMM) lsquocentrersquo versus lsquostartrsquo estimSE frac14 0049 z frac14 294 P frac14 0009 lsquoendrsquo versus lsquocentrersquo estimate frac14 029 SE frac14 0058 z frac14 50P frac14 0003 lsquoendrsquo versus lsquostartrsquo estimate frac14 0012 SE frac14 0039 z frac14 031 P frac14 094 lsquoendrsquo versusestimate frac14 016 SE frac14 006 z frac14 278 P frac14 0014 lsquocentrersquo versus lsquostartrsquo estimate frac14 039 SE frac14P lt 0001

conditions Indeed BW were performed roughly 20 (111 ms)faster during singing whereas the duration of TA did not differ(Fig 5) Detailed frame-by-frame analysis revealed that the shorterBW duration during song was due to a faster stroke phase of theBW while preparation and poststroke phases lasted comparableamounts of time during song and during silence This suggests thatbirds can modulate the duration of BW during song facilitatingintegration of song and body movements

BW and TA were Correlated with Amount of Song

To further pursue whether song and body movements are co-ordinated we analysed individual birds Indeed the more motifs amale sang the more BW and TA he performed (Fig 6a and b) Incontrast the number of hops was not correlated with the amountof singing (Fig 6c) even though hops occurred significantly moreoften during song than nonsong (Fig 4c) Comparing the numberof movements to the number of bouts sung by each bird yieldedvery similar results (Pearson product moment correlation BWversus bout t18 frac14 245 P frac14 0025 TA versus bout t18 frac14 299P frac14 00077 hop versus bout t8 frac14 0098 P frac14 092 Fig A2) ThusBW and TA appear to be more directly associated with song thanhops

(c)

(f)

0

02

04

06

08

Nonsong Song Nonsong

N = 10TA Hop

08

1

06

04

02

0Endentre Start EndCentre

ts show median (black horizontal line) 25 and 75 quartiles (box segment below orkers) and outliers (points) P lt 005 P lt 001 P lt 0001 Paired t test (a) BW songsong versus nonsong t9 frac14 514 P lt 0001 Number of (d) BW (e) TA and (f) hops duringences in all videos Grey lines connect data of the same individual Black horizontal barsate frac14 043 SE frac14 0058 z frac14 743 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 0141 P lt 0001 (e) LMM lsquocentrersquo versus lsquostartrsquo estimate frac14 014 SE frac14 0042 z frac14 324lsquocentrersquo estimate frac14 015 SE frac14 005 z frac14 271 P frac14 0018 (f) LMM lsquoendrsquo versus lsquocentrersquo008 z frac14 496 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 024 SE frac14 005 z frac14 452

N = 20 N = 17

02

03

04

05

06

07

08M

ean

du

rati

on (

s)

Song Nonsong Song Nonsong

BW TA

Figure 5 Duration of BW and TA movements during song and nonsong For each birdthe average duration of BW (Nfrac1420 birds) and TA (Nfrac1417 birds) were calculatedP lt 0001 Paired t test BW t19 frac14 615 P lt 0001 TA t16 frac14 133 P frac14 020) Forbox plot specifications see legend to Fig 4

R Ullrich et al Animal Behaviour 112 (2016) 285e300290

Hop Rates During Song Correlated with those Outside Song

Individuals varied considerably in frequency of BW TA and hopsduring song We wondered whether an individuals propensity toperform more or less song-associated movements was related tohow often these movements occurred when they were not singingInterestingly the numbers of hops (Fig A3c) during song andnonsong were significantly correlated whereas this was not thecase for BW (Fig A3a) and TA (Fig A3b)

During Song Numbers of BW and TA were Tightly Related

Given that all three movements occurred more frequentlywith song than outside the song context (Fig 4aec) we checkedwhether all three movements are part of an integrated songchoreography Consistent with this notion during song but notoutside the song context the number of BW and TA were morerelated to each other than TA were with hops or BW with hops(Fig 7aec Pearson product moment correlation song TA versusBW t18 frac14 204 P frac14 0056 TA versus hop t8 frac14 016 P frac14 088 BWversus hop t8 frac14 017 P frac14 087 nonsong BW versus TAt18 frac14 008 P frac14 093 hop versus TA t8 frac14 116 P frac14 028 9 hopversus BW t8 frac14 038 P frac14 071) This finding together with theresults shown in Fig 6 raised the possibility that BW and TA area more tightly integrated part of the song choreography thanhops

Hops Coincided with Particular Notes

To determine whether hops were in fact less coordinated withsong than BW and TA we quantified when hops occurred inrelationship to song using frame by frame video analysis Because

hopping behaviour is often accompanied by calls (Moorman ampBolhuis 2013 p 112 Zann 1996 p 197) we measured the in-terval between a hop and the introductory the first and the lastmotif notes We found that most hops coincided exactly orclosely in time with the utterance of a note or call This wasparticularly striking for the introductory notes (Fig 8a) Notehowever that hops and vocalizations were not obligatorilycoupled

Might the striking coincidence of hops and introductory notesstem from physical constraints of hopping such as a minimuminterval between hops mandated by movement mechanics Toanswer this question we analysed how the intervals between twohops were distributed Only two hop intervals out of 588 wereshorter than 200 ms probably reflecting the limit of how fast twosuccessive hops can be performed During song 49 of all interhopintervals ranged between 200 and 1000 ms (Fig 8b) Interhop in-tervals of this range of durations were between 200 and 400 mslong Hops of this duration were almost twice as numerous duringsong than during nonsong (24 versus 13) Although birds per-formed a very wide range of interhop intervals during song (seerightmost columns Fig 8b) we observed 24 of them within thesame time span as interintroductory note intervals (mean plusmn -SD frac14 255 plusmn 215 ms) Although in both contexts hop intervals be-tween 200 and 400 msweremost frequent the high coincidence ofhops with introductory notes therefore does not appear to be asimple by-product of a narrow range of hop interval durationsmandated by physical constraints (Fig 8a) Instead it is consistentwith the possibility that hops and notes coincide as a consequenceof voluntary control

Were hops and calls also associated when zebra finches werenot singing We analysed the duration between a hop and the callclosest in time and found that 56 of all hopping behaviour clus-tered in a 2 s timewindowaround calls (ie1 s before plus 1 s after)Twenty per cent of all hops were directly associated with calls(Fig 8c and see the Appendix) We ruled out the possibility that theclose association of hops and calls was a function of two indepen-dent events being associated coincidentally hops and calls weresignificantly more often linked in time than would be expected bychance (Fig 8d hop estimated versus observed one-tailed paired ttest t9 frac14 314 P lt 001)

Behaviour Transition Ratios Differed from those Expected

To analyse the sequence of movements we transcribed theorder of transitions between BW TA and hops following eachother with intervals shorter than 2 s Longer intervals wereconsidered the start and end of a transition string Fig 9 shows thesequence diagram of movement transition probabilities across all10 birds from experiment C during bouts Transition probabilitiesthat would be expected if the three movements were equallylikely to follow each other were calculated based on the observednumber of movements and transition strings (see Appendix fordetails) Observed probabilities of all transition types in theirentirety differed significantly from the expected values(c2

14 frac14 11678 P lt 0001) Transitions from TA to TA (LMMc2

1 frac141192 P frac14 00005 difference frac14 011 plusmn 002 SE) and fromhop to TA (LMM c2

1 frac14864 P frac14 00033 difference frac14 007 plusmn 002SE) occurred significantly less frequently than expected by chancewhile transitions from hop to hop were significantly morefrequent (LMM c2

1 frac141072 P frac14 0001 difference frac14 thorn015 plusmn 003SE see also Figs A4 and A5)

In individual birds transition string length varied between 2and 17 movements Not all possible movement combinations

P = 0014

R2 = 0293

R2 = 031

R2 = 0076

N = 20

N = 10

N = 20

300

100

150

100

50

90

80

70

60

50

40

30

100 150 250 300 350

0

No of motifs

No

of

hop

sN

o o

f TA

(a)

(b)

(c)

400

No

of

BW

200

P = 0011

P = 044

200

Figure 6 Number of (a) BW (b) TA and (c) hops in relation to number of motifs sungPearson product moment correlation BW versus motif t18 frac14 27 P lt 005 TA versusmotif t18 frac14 284 P lt 005 hop versus motif t8 frac14 081 P frac14 044

R Ullrich et al Animal Behaviour 112 (2016) 285e300 291

occurred and some were particularly frequent (Table A2) Consis-tent with our hypothesis that sequences of movements during songare part of a choreography the frequency distribution of stringlength was skewed towards longer strings during song than duringnonsong (Fig A6)

Finally we examined whether age (and by inference experi-ence) correlatedwith dance vigourWe analysed the number of BWTA and hops in relation to age but did not find a systematic asso-ciation as reported before (Williams 2001 Pearson productmoment correlation age versus BW t18 frac14 014 P frac14 088 ageversus TA t18 frac14 15 P frac14 015 age versus hop t8 frac14 084P frac14 043)

DISCUSSION

Here we comprehensively show for the first time multipleways in which the expression of dance is strongly but not oblig-atorily associated with the expression of song in zebra finchesStereotypic movements that is BW TA and hops occurredsignificantly more during song than during silence All threemovements clustered at the start and end of motifs and hopscoincided with notes particularly the introductory but also thefirst and last motif notes BW were performed faster during songthan during silence but TA were not The more birds sang themore BW and TA occurred Dance sequences were flexibly but notrandomly arranged Together these results suggest a choreogra-phy of song and dance that signals courtship intensity A previousstudy (Williams 2001) did not find a strongly patterned associa-tion between song and dance movements which might bebecause hops forward left right back up and down headmovements were pooled However Williams (2001 p 3505)observed qualitatively that lsquothe relatively infrequent dancemovements appear to be initiated at a number of specific lsquohotspotsrsquo within the songrsquo

Clustering of BW TA and hops at the beginning and end ofmotifs may serve as lsquoinitiation and closurersquo signals The male coulddraw attention to his courtship before the relatively quiet songbecomes audible to the receivers The repeated 180 turning of thebird while singing as he approaches the female is associated with aregular change in song sound amplitude This could also allow herto discriminate the courting males sound pattern from the noisyenvironment of the vocalizing flock mates and provide an exampleof lsquospatial release from maskingrsquo (Bee amp Micheyl 2008) Gesturessuch as BW and TA at the beginning and end of motifs might alsofocus the females attention on the motif structure and thus aid inthe evaluation of song stereotypy a feature relevant for femalechoice (Riebel 2009) When analysing the location of movementswithin the motif we did not distinguish the very first and last fromthe other motifs of a bout However the number of movements abird performed correlated with both the motif and bout count to avery similar degree suggesting that the placement of bodymovements is not primarily tied to the beginning or end of a songbout

Courtship intensity in zebra finch males is influenced by thesocial background (Ruploh Bischof amp Engelhardt 2012) the sizeof the experimental cage the experimental procedure itself(Immelmann 1959 p 447) dopamine turnover in brain areascontrolling the motor patterning of song (Rauceo et al 2008) andthe females reaction (Zann 1996 pp 171e173) As we useddifferent cage sizes and experimental set-ups our resultsencompass this variability yet particular movements wereconsistently and significantly associated with courtship song Avigorously courting male sings more motifs per unit time (Riebel2009) and we show that the number of song motifs in individualmales also strongly predicts their BW and TA activity Moreover

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

R Ullrich et al Animal Behaviour 112 (2016) 285e300 289

around movements (TA) into a preparation phase stroke andpoststroke phase (Fig A1) Hop movements were scored as pointevents (Fig A1) To investigate whether hops BW and TA werecoordinated with song we quantified occurrences and timing ofthese movements both during song and nonsong segments(Fig 3)

Body Movements were Associated with Song

All three body movements occurred significantly more often persecond during song than nonsong (Fig 4aec) Interestingly birdsinitiated and ended song motifs significantly more often with BWTA and hops than in the lsquocentrersquo of motifs (Fig 4def for definitionof motif divisions see Methods Fig 3) Also BW and hops but notTA were more numerous at the lsquostartrsquo than at the lsquoendrsquo of motifs(Fig 4def) These findings were consistent with coordination be-tween song and dance

During Song BW but not TA were Performed Faster

If body movements were coordinated with song they might beperformed at different durations during singing and nonsinging Toassess this we compared the durations of BW and TA in the two

(a) (b)

(d) (e)

0

02

04

06

08

0

02

04

06

08

Song Nonsong Song

N = 20 N = 20BW

0

05

1

15

08

06

04

02

0Start EndCentre Start C

Nu

mbe

r of

occ

urr

ence

ss

Figure 4 (aec) Number of body movementss during song and nonsong segments Box ploabove median) outermost values within the range of 15 times the respective quartiles (whisversus nonsong t19 frac14 455 P lt 001 (b) TA song versus nonsong t19 frac14 42 P lt 001 (c) hopsthe lsquostartrsquo lsquocentrersquo and lsquoendrsquo of song motifs Grey points represent the birds average of occurrdepict the groups average (d) Linear mixed model (LMM) lsquocentrersquo versus lsquostartrsquo estimSE frac14 0049 z frac14 294 P frac14 0009 lsquoendrsquo versus lsquocentrersquo estimate frac14 029 SE frac14 0058 z frac14 50P frac14 0003 lsquoendrsquo versus lsquostartrsquo estimate frac14 0012 SE frac14 0039 z frac14 031 P frac14 094 lsquoendrsquo versusestimate frac14 016 SE frac14 006 z frac14 278 P frac14 0014 lsquocentrersquo versus lsquostartrsquo estimate frac14 039 SE frac14P lt 0001

conditions Indeed BW were performed roughly 20 (111 ms)faster during singing whereas the duration of TA did not differ(Fig 5) Detailed frame-by-frame analysis revealed that the shorterBW duration during song was due to a faster stroke phase of theBW while preparation and poststroke phases lasted comparableamounts of time during song and during silence This suggests thatbirds can modulate the duration of BW during song facilitatingintegration of song and body movements

BW and TA were Correlated with Amount of Song

To further pursue whether song and body movements are co-ordinated we analysed individual birds Indeed the more motifs amale sang the more BW and TA he performed (Fig 6a and b) Incontrast the number of hops was not correlated with the amountof singing (Fig 6c) even though hops occurred significantly moreoften during song than nonsong (Fig 4c) Comparing the numberof movements to the number of bouts sung by each bird yieldedvery similar results (Pearson product moment correlation BWversus bout t18 frac14 245 P frac14 0025 TA versus bout t18 frac14 299P frac14 00077 hop versus bout t8 frac14 0098 P frac14 092 Fig A2) ThusBW and TA appear to be more directly associated with song thanhops

(c)

(f)

0

02

04

06

08

Nonsong Song Nonsong

N = 10TA Hop

08

1

06

04

02

0Endentre Start EndCentre

ts show median (black horizontal line) 25 and 75 quartiles (box segment below orkers) and outliers (points) P lt 005 P lt 001 P lt 0001 Paired t test (a) BW songsong versus nonsong t9 frac14 514 P lt 0001 Number of (d) BW (e) TA and (f) hops duringences in all videos Grey lines connect data of the same individual Black horizontal barsate frac14 043 SE frac14 0058 z frac14 743 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 0141 P lt 0001 (e) LMM lsquocentrersquo versus lsquostartrsquo estimate frac14 014 SE frac14 0042 z frac14 324lsquocentrersquo estimate frac14 015 SE frac14 005 z frac14 271 P frac14 0018 (f) LMM lsquoendrsquo versus lsquocentrersquo008 z frac14 496 P lt 0001 lsquoendrsquo versus lsquostartrsquo estimate frac14 024 SE frac14 005 z frac14 452

N = 20 N = 17

02

03

04

05

06

07

08M

ean

du

rati

on (

s)

Song Nonsong Song Nonsong

BW TA

Figure 5 Duration of BW and TA movements during song and nonsong For each birdthe average duration of BW (Nfrac1420 birds) and TA (Nfrac1417 birds) were calculatedP lt 0001 Paired t test BW t19 frac14 615 P lt 0001 TA t16 frac14 133 P frac14 020) Forbox plot specifications see legend to Fig 4

R Ullrich et al Animal Behaviour 112 (2016) 285e300290

Hop Rates During Song Correlated with those Outside Song

Individuals varied considerably in frequency of BW TA and hopsduring song We wondered whether an individuals propensity toperform more or less song-associated movements was related tohow often these movements occurred when they were not singingInterestingly the numbers of hops (Fig A3c) during song andnonsong were significantly correlated whereas this was not thecase for BW (Fig A3a) and TA (Fig A3b)

During Song Numbers of BW and TA were Tightly Related

Given that all three movements occurred more frequentlywith song than outside the song context (Fig 4aec) we checkedwhether all three movements are part of an integrated songchoreography Consistent with this notion during song but notoutside the song context the number of BW and TA were morerelated to each other than TA were with hops or BW with hops(Fig 7aec Pearson product moment correlation song TA versusBW t18 frac14 204 P frac14 0056 TA versus hop t8 frac14 016 P frac14 088 BWversus hop t8 frac14 017 P frac14 087 nonsong BW versus TAt18 frac14 008 P frac14 093 hop versus TA t8 frac14 116 P frac14 028 9 hopversus BW t8 frac14 038 P frac14 071) This finding together with theresults shown in Fig 6 raised the possibility that BW and TA area more tightly integrated part of the song choreography thanhops

Hops Coincided with Particular Notes

To determine whether hops were in fact less coordinated withsong than BW and TA we quantified when hops occurred inrelationship to song using frame by frame video analysis Because

hopping behaviour is often accompanied by calls (Moorman ampBolhuis 2013 p 112 Zann 1996 p 197) we measured the in-terval between a hop and the introductory the first and the lastmotif notes We found that most hops coincided exactly orclosely in time with the utterance of a note or call This wasparticularly striking for the introductory notes (Fig 8a) Notehowever that hops and vocalizations were not obligatorilycoupled

Might the striking coincidence of hops and introductory notesstem from physical constraints of hopping such as a minimuminterval between hops mandated by movement mechanics Toanswer this question we analysed how the intervals between twohops were distributed Only two hop intervals out of 588 wereshorter than 200 ms probably reflecting the limit of how fast twosuccessive hops can be performed During song 49 of all interhopintervals ranged between 200 and 1000 ms (Fig 8b) Interhop in-tervals of this range of durations were between 200 and 400 mslong Hops of this duration were almost twice as numerous duringsong than during nonsong (24 versus 13) Although birds per-formed a very wide range of interhop intervals during song (seerightmost columns Fig 8b) we observed 24 of them within thesame time span as interintroductory note intervals (mean plusmn -SD frac14 255 plusmn 215 ms) Although in both contexts hop intervals be-tween 200 and 400 msweremost frequent the high coincidence ofhops with introductory notes therefore does not appear to be asimple by-product of a narrow range of hop interval durationsmandated by physical constraints (Fig 8a) Instead it is consistentwith the possibility that hops and notes coincide as a consequenceof voluntary control

Were hops and calls also associated when zebra finches werenot singing We analysed the duration between a hop and the callclosest in time and found that 56 of all hopping behaviour clus-tered in a 2 s timewindowaround calls (ie1 s before plus 1 s after)Twenty per cent of all hops were directly associated with calls(Fig 8c and see the Appendix) We ruled out the possibility that theclose association of hops and calls was a function of two indepen-dent events being associated coincidentally hops and calls weresignificantly more often linked in time than would be expected bychance (Fig 8d hop estimated versus observed one-tailed paired ttest t9 frac14 314 P lt 001)

Behaviour Transition Ratios Differed from those Expected

To analyse the sequence of movements we transcribed theorder of transitions between BW TA and hops following eachother with intervals shorter than 2 s Longer intervals wereconsidered the start and end of a transition string Fig 9 shows thesequence diagram of movement transition probabilities across all10 birds from experiment C during bouts Transition probabilitiesthat would be expected if the three movements were equallylikely to follow each other were calculated based on the observednumber of movements and transition strings (see Appendix fordetails) Observed probabilities of all transition types in theirentirety differed significantly from the expected values(c2

14 frac14 11678 P lt 0001) Transitions from TA to TA (LMMc2

1 frac141192 P frac14 00005 difference frac14 011 plusmn 002 SE) and fromhop to TA (LMM c2

1 frac14864 P frac14 00033 difference frac14 007 plusmn 002SE) occurred significantly less frequently than expected by chancewhile transitions from hop to hop were significantly morefrequent (LMM c2

1 frac141072 P frac14 0001 difference frac14 thorn015 plusmn 003SE see also Figs A4 and A5)

In individual birds transition string length varied between 2and 17 movements Not all possible movement combinations

P = 0014

R2 = 0293

R2 = 031

R2 = 0076

N = 20

N = 10

N = 20

300

100

150

100

50

90

80

70

60

50

40

30

100 150 250 300 350

0

No of motifs

No

of

hop

sN

o o

f TA

(a)

(b)

(c)

400

No

of

BW

200

P = 0011

P = 044

200

Figure 6 Number of (a) BW (b) TA and (c) hops in relation to number of motifs sungPearson product moment correlation BW versus motif t18 frac14 27 P lt 005 TA versusmotif t18 frac14 284 P lt 005 hop versus motif t8 frac14 081 P frac14 044

R Ullrich et al Animal Behaviour 112 (2016) 285e300 291

occurred and some were particularly frequent (Table A2) Consis-tent with our hypothesis that sequences of movements during songare part of a choreography the frequency distribution of stringlength was skewed towards longer strings during song than duringnonsong (Fig A6)

Finally we examined whether age (and by inference experi-ence) correlatedwith dance vigourWe analysed the number of BWTA and hops in relation to age but did not find a systematic asso-ciation as reported before (Williams 2001 Pearson productmoment correlation age versus BW t18 frac14 014 P frac14 088 ageversus TA t18 frac14 15 P frac14 015 age versus hop t8 frac14 084P frac14 043)

DISCUSSION

Here we comprehensively show for the first time multipleways in which the expression of dance is strongly but not oblig-atorily associated with the expression of song in zebra finchesStereotypic movements that is BW TA and hops occurredsignificantly more during song than during silence All threemovements clustered at the start and end of motifs and hopscoincided with notes particularly the introductory but also thefirst and last motif notes BW were performed faster during songthan during silence but TA were not The more birds sang themore BW and TA occurred Dance sequences were flexibly but notrandomly arranged Together these results suggest a choreogra-phy of song and dance that signals courtship intensity A previousstudy (Williams 2001) did not find a strongly patterned associa-tion between song and dance movements which might bebecause hops forward left right back up and down headmovements were pooled However Williams (2001 p 3505)observed qualitatively that lsquothe relatively infrequent dancemovements appear to be initiated at a number of specific lsquohotspotsrsquo within the songrsquo

Clustering of BW TA and hops at the beginning and end ofmotifs may serve as lsquoinitiation and closurersquo signals The male coulddraw attention to his courtship before the relatively quiet songbecomes audible to the receivers The repeated 180 turning of thebird while singing as he approaches the female is associated with aregular change in song sound amplitude This could also allow herto discriminate the courting males sound pattern from the noisyenvironment of the vocalizing flock mates and provide an exampleof lsquospatial release from maskingrsquo (Bee amp Micheyl 2008) Gesturessuch as BW and TA at the beginning and end of motifs might alsofocus the females attention on the motif structure and thus aid inthe evaluation of song stereotypy a feature relevant for femalechoice (Riebel 2009) When analysing the location of movementswithin the motif we did not distinguish the very first and last fromthe other motifs of a bout However the number of movements abird performed correlated with both the motif and bout count to avery similar degree suggesting that the placement of bodymovements is not primarily tied to the beginning or end of a songbout

Courtship intensity in zebra finch males is influenced by thesocial background (Ruploh Bischof amp Engelhardt 2012) the sizeof the experimental cage the experimental procedure itself(Immelmann 1959 p 447) dopamine turnover in brain areascontrolling the motor patterning of song (Rauceo et al 2008) andthe females reaction (Zann 1996 pp 171e173) As we useddifferent cage sizes and experimental set-ups our resultsencompass this variability yet particular movements wereconsistently and significantly associated with courtship song Avigorously courting male sings more motifs per unit time (Riebel2009) and we show that the number of song motifs in individualmales also strongly predicts their BW and TA activity Moreover

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

N = 20 N = 17

02

03

04

05

06

07

08M

ean

du

rati

on (

s)

Song Nonsong Song Nonsong

BW TA

Figure 5 Duration of BW and TA movements during song and nonsong For each birdthe average duration of BW (Nfrac1420 birds) and TA (Nfrac1417 birds) were calculatedP lt 0001 Paired t test BW t19 frac14 615 P lt 0001 TA t16 frac14 133 P frac14 020) Forbox plot specifications see legend to Fig 4

R Ullrich et al Animal Behaviour 112 (2016) 285e300290

Hop Rates During Song Correlated with those Outside Song

Individuals varied considerably in frequency of BW TA and hopsduring song We wondered whether an individuals propensity toperform more or less song-associated movements was related tohow often these movements occurred when they were not singingInterestingly the numbers of hops (Fig A3c) during song andnonsong were significantly correlated whereas this was not thecase for BW (Fig A3a) and TA (Fig A3b)

During Song Numbers of BW and TA were Tightly Related

Given that all three movements occurred more frequentlywith song than outside the song context (Fig 4aec) we checkedwhether all three movements are part of an integrated songchoreography Consistent with this notion during song but notoutside the song context the number of BW and TA were morerelated to each other than TA were with hops or BW with hops(Fig 7aec Pearson product moment correlation song TA versusBW t18 frac14 204 P frac14 0056 TA versus hop t8 frac14 016 P frac14 088 BWversus hop t8 frac14 017 P frac14 087 nonsong BW versus TAt18 frac14 008 P frac14 093 hop versus TA t8 frac14 116 P frac14 028 9 hopversus BW t8 frac14 038 P frac14 071) This finding together with theresults shown in Fig 6 raised the possibility that BW and TA area more tightly integrated part of the song choreography thanhops

Hops Coincided with Particular Notes

To determine whether hops were in fact less coordinated withsong than BW and TA we quantified when hops occurred inrelationship to song using frame by frame video analysis Because

hopping behaviour is often accompanied by calls (Moorman ampBolhuis 2013 p 112 Zann 1996 p 197) we measured the in-terval between a hop and the introductory the first and the lastmotif notes We found that most hops coincided exactly orclosely in time with the utterance of a note or call This wasparticularly striking for the introductory notes (Fig 8a) Notehowever that hops and vocalizations were not obligatorilycoupled

Might the striking coincidence of hops and introductory notesstem from physical constraints of hopping such as a minimuminterval between hops mandated by movement mechanics Toanswer this question we analysed how the intervals between twohops were distributed Only two hop intervals out of 588 wereshorter than 200 ms probably reflecting the limit of how fast twosuccessive hops can be performed During song 49 of all interhopintervals ranged between 200 and 1000 ms (Fig 8b) Interhop in-tervals of this range of durations were between 200 and 400 mslong Hops of this duration were almost twice as numerous duringsong than during nonsong (24 versus 13) Although birds per-formed a very wide range of interhop intervals during song (seerightmost columns Fig 8b) we observed 24 of them within thesame time span as interintroductory note intervals (mean plusmn -SD frac14 255 plusmn 215 ms) Although in both contexts hop intervals be-tween 200 and 400 msweremost frequent the high coincidence ofhops with introductory notes therefore does not appear to be asimple by-product of a narrow range of hop interval durationsmandated by physical constraints (Fig 8a) Instead it is consistentwith the possibility that hops and notes coincide as a consequenceof voluntary control

Were hops and calls also associated when zebra finches werenot singing We analysed the duration between a hop and the callclosest in time and found that 56 of all hopping behaviour clus-tered in a 2 s timewindowaround calls (ie1 s before plus 1 s after)Twenty per cent of all hops were directly associated with calls(Fig 8c and see the Appendix) We ruled out the possibility that theclose association of hops and calls was a function of two indepen-dent events being associated coincidentally hops and calls weresignificantly more often linked in time than would be expected bychance (Fig 8d hop estimated versus observed one-tailed paired ttest t9 frac14 314 P lt 001)

Behaviour Transition Ratios Differed from those Expected

To analyse the sequence of movements we transcribed theorder of transitions between BW TA and hops following eachother with intervals shorter than 2 s Longer intervals wereconsidered the start and end of a transition string Fig 9 shows thesequence diagram of movement transition probabilities across all10 birds from experiment C during bouts Transition probabilitiesthat would be expected if the three movements were equallylikely to follow each other were calculated based on the observednumber of movements and transition strings (see Appendix fordetails) Observed probabilities of all transition types in theirentirety differed significantly from the expected values(c2

14 frac14 11678 P lt 0001) Transitions from TA to TA (LMMc2

1 frac141192 P frac14 00005 difference frac14 011 plusmn 002 SE) and fromhop to TA (LMM c2

1 frac14864 P frac14 00033 difference frac14 007 plusmn 002SE) occurred significantly less frequently than expected by chancewhile transitions from hop to hop were significantly morefrequent (LMM c2

1 frac141072 P frac14 0001 difference frac14 thorn015 plusmn 003SE see also Figs A4 and A5)

In individual birds transition string length varied between 2and 17 movements Not all possible movement combinations

P = 0014

R2 = 0293

R2 = 031

R2 = 0076

N = 20

N = 10

N = 20

300

100

150

100

50

90

80

70

60

50

40

30

100 150 250 300 350

0

No of motifs

No

of

hop

sN

o o

f TA

(a)

(b)

(c)

400

No

of

BW

200

P = 0011

P = 044

200

Figure 6 Number of (a) BW (b) TA and (c) hops in relation to number of motifs sungPearson product moment correlation BW versus motif t18 frac14 27 P lt 005 TA versusmotif t18 frac14 284 P lt 005 hop versus motif t8 frac14 081 P frac14 044

R Ullrich et al Animal Behaviour 112 (2016) 285e300 291

occurred and some were particularly frequent (Table A2) Consis-tent with our hypothesis that sequences of movements during songare part of a choreography the frequency distribution of stringlength was skewed towards longer strings during song than duringnonsong (Fig A6)

Finally we examined whether age (and by inference experi-ence) correlatedwith dance vigourWe analysed the number of BWTA and hops in relation to age but did not find a systematic asso-ciation as reported before (Williams 2001 Pearson productmoment correlation age versus BW t18 frac14 014 P frac14 088 ageversus TA t18 frac14 15 P frac14 015 age versus hop t8 frac14 084P frac14 043)

DISCUSSION

Here we comprehensively show for the first time multipleways in which the expression of dance is strongly but not oblig-atorily associated with the expression of song in zebra finchesStereotypic movements that is BW TA and hops occurredsignificantly more during song than during silence All threemovements clustered at the start and end of motifs and hopscoincided with notes particularly the introductory but also thefirst and last motif notes BW were performed faster during songthan during silence but TA were not The more birds sang themore BW and TA occurred Dance sequences were flexibly but notrandomly arranged Together these results suggest a choreogra-phy of song and dance that signals courtship intensity A previousstudy (Williams 2001) did not find a strongly patterned associa-tion between song and dance movements which might bebecause hops forward left right back up and down headmovements were pooled However Williams (2001 p 3505)observed qualitatively that lsquothe relatively infrequent dancemovements appear to be initiated at a number of specific lsquohotspotsrsquo within the songrsquo

Clustering of BW TA and hops at the beginning and end ofmotifs may serve as lsquoinitiation and closurersquo signals The male coulddraw attention to his courtship before the relatively quiet songbecomes audible to the receivers The repeated 180 turning of thebird while singing as he approaches the female is associated with aregular change in song sound amplitude This could also allow herto discriminate the courting males sound pattern from the noisyenvironment of the vocalizing flock mates and provide an exampleof lsquospatial release from maskingrsquo (Bee amp Micheyl 2008) Gesturessuch as BW and TA at the beginning and end of motifs might alsofocus the females attention on the motif structure and thus aid inthe evaluation of song stereotypy a feature relevant for femalechoice (Riebel 2009) When analysing the location of movementswithin the motif we did not distinguish the very first and last fromthe other motifs of a bout However the number of movements abird performed correlated with both the motif and bout count to avery similar degree suggesting that the placement of bodymovements is not primarily tied to the beginning or end of a songbout

Courtship intensity in zebra finch males is influenced by thesocial background (Ruploh Bischof amp Engelhardt 2012) the sizeof the experimental cage the experimental procedure itself(Immelmann 1959 p 447) dopamine turnover in brain areascontrolling the motor patterning of song (Rauceo et al 2008) andthe females reaction (Zann 1996 pp 171e173) As we useddifferent cage sizes and experimental set-ups our resultsencompass this variability yet particular movements wereconsistently and significantly associated with courtship song Avigorously courting male sings more motifs per unit time (Riebel2009) and we show that the number of song motifs in individualmales also strongly predicts their BW and TA activity Moreover

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

P = 0014

R2 = 0293

R2 = 031

R2 = 0076

N = 20

N = 10

N = 20

300

100

150

100

50

90

80

70

60

50

40

30

100 150 250 300 350

0

No of motifs

No

of

hop

sN

o o

f TA

(a)

(b)

(c)

400

No

of

BW

200

P = 0011

P = 044

200

Figure 6 Number of (a) BW (b) TA and (c) hops in relation to number of motifs sungPearson product moment correlation BW versus motif t18 frac14 27 P lt 005 TA versusmotif t18 frac14 284 P lt 005 hop versus motif t8 frac14 081 P frac14 044

R Ullrich et al Animal Behaviour 112 (2016) 285e300 291

occurred and some were particularly frequent (Table A2) Consis-tent with our hypothesis that sequences of movements during songare part of a choreography the frequency distribution of stringlength was skewed towards longer strings during song than duringnonsong (Fig A6)

Finally we examined whether age (and by inference experi-ence) correlatedwith dance vigourWe analysed the number of BWTA and hops in relation to age but did not find a systematic asso-ciation as reported before (Williams 2001 Pearson productmoment correlation age versus BW t18 frac14 014 P frac14 088 ageversus TA t18 frac14 15 P frac14 015 age versus hop t8 frac14 084P frac14 043)

DISCUSSION

Here we comprehensively show for the first time multipleways in which the expression of dance is strongly but not oblig-atorily associated with the expression of song in zebra finchesStereotypic movements that is BW TA and hops occurredsignificantly more during song than during silence All threemovements clustered at the start and end of motifs and hopscoincided with notes particularly the introductory but also thefirst and last motif notes BW were performed faster during songthan during silence but TA were not The more birds sang themore BW and TA occurred Dance sequences were flexibly but notrandomly arranged Together these results suggest a choreogra-phy of song and dance that signals courtship intensity A previousstudy (Williams 2001) did not find a strongly patterned associa-tion between song and dance movements which might bebecause hops forward left right back up and down headmovements were pooled However Williams (2001 p 3505)observed qualitatively that lsquothe relatively infrequent dancemovements appear to be initiated at a number of specific lsquohotspotsrsquo within the songrsquo

Clustering of BW TA and hops at the beginning and end ofmotifs may serve as lsquoinitiation and closurersquo signals The male coulddraw attention to his courtship before the relatively quiet songbecomes audible to the receivers The repeated 180 turning of thebird while singing as he approaches the female is associated with aregular change in song sound amplitude This could also allow herto discriminate the courting males sound pattern from the noisyenvironment of the vocalizing flock mates and provide an exampleof lsquospatial release from maskingrsquo (Bee amp Micheyl 2008) Gesturessuch as BW and TA at the beginning and end of motifs might alsofocus the females attention on the motif structure and thus aid inthe evaluation of song stereotypy a feature relevant for femalechoice (Riebel 2009) When analysing the location of movementswithin the motif we did not distinguish the very first and last fromthe other motifs of a bout However the number of movements abird performed correlated with both the motif and bout count to avery similar degree suggesting that the placement of bodymovements is not primarily tied to the beginning or end of a songbout

Courtship intensity in zebra finch males is influenced by thesocial background (Ruploh Bischof amp Engelhardt 2012) the sizeof the experimental cage the experimental procedure itself(Immelmann 1959 p 447) dopamine turnover in brain areascontrolling the motor patterning of song (Rauceo et al 2008) andthe females reaction (Zann 1996 pp 171e173) As we useddifferent cage sizes and experimental set-ups our resultsencompass this variability yet particular movements wereconsistently and significantly associated with courtship song Avigorously courting male sings more motifs per unit time (Riebel2009) and we show that the number of song motifs in individualmales also strongly predicts their BW and TA activity Moreover

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

03

025

02

015

01

005

00 02 04 06

No of BWs

No

of

TA

s

P = 0056

N = 20

R2 = 0188(a) 03

025

02

015

01

005

00 02 04 06

No of hopssN

o o

f T

As

P = 088

N = 10

R2 = 000324(b) 07

06

05

04

03

02

01

00 02 04 06

No of hopss

No

of

BW

s

P = 071

N = 10

R2 = 00176(c)

Figure 7 Correlations between (a) number of TA and BW (b) number of TA and hops and (c) number of BW and hops Hops performed as part of a TA were removed prior to TAanalysis See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300292

TA were tightly related with BW during singing but not outsidethe song context Together these results are consistent with thenotion that TA and BW indicate intensity of courtship in a linearfashion

140

120

100

60

40

20

0

100

80

60

20

0

N =10

N =10 N =10

ndash1

ndash05

ndash05

ndash05051 1ndash1 ndash1

-10 -05

0 0

Timii_call

(a)

(b) SongNonsong

(c)

lsquoStartrsquo

006

005

004

003

001

001 05 07 09 1-2 gt203

Hops associa

80

No

of h

ops

05

002

Hop

ss

40

No

of h

ops

Occurrence of H-H intervals (s)

Figure 8 (a) Frequency histogram depicting the number of hops associated with song notshowed both feet displaced from the perch during a hop fell within the duration of a notenumbers on x-axis) a note the duration between the hop and the closest note are depictehighlighted by different grey shadings (b) Histogram depicting the distribution of interva(striped) HeH song versus HeH nonsong paired t test t9 frac14 36 P lt 001 The remaining inciation between calls (plotted as time 0) and hops occurring outside the song context (d) Btwo events was calculated See text for statistics For box plot specifications see legend of F

Interindividual differences were not only observed in courtshipintensity but also existed in overall activity levels For instance thenumber of hops performed during the time when birds were notsinging was predictive of the number of hops during song

50

150

0

N =10

ndash05

ndash0505

05

051 11

0 05 1

ndash1 ndash10 0 0e_callLF

e (s)

(d)

lsquoCentrersquo lsquoEndrsquo

ted with calls (s)Observed

100

Hop

s as

soci

ated

wit

h c

alls

Estimated

es We scored a hop as coincident with a song note when the 16 ms video frame that(0 on x-axis) For hops occurring before (minus numbers on x-axis) or after (positived in 30 ms bins The larger song segments (lsquostartrsquo lsquocentrersquo lsquoendrsquo see Figs 2 and 3) arels between hops (HeH intervals) performed during song (shaded grey) and nonsongtervals are pooled in the two rightmost columns (c) Histogram illustrating the asso-ased on the number and duration of hops and calls the estimated coincidence of theseig 4

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

03

026

019

051

043

049033

02

028

033

018

025024

013

023

024

036

025023

011018

026

023

018033

026

034

026025

018

BWN = 404

TAN = 280

HopN = 506

StartN=56

StartN=120

StartN=60

EndN=92

EndN=57

EndN=87

Start ndash BW ndash TA ndash BW ndash End

Start ndash hop ndash hop ndash hop ndash hop ndash TA ndash End

Start ndash BW ndash TA ndash BW ndash TA ndash hop ndash TA ndash End

(a)

(b)

Figure 9 (a) Sequence diagram of BW TA and hops as well as start and end points of dance during song of 10 birds Observed transition probabilities (black) are indicated byarrows Their size corresponds to the numerical values indicated next to the arrow Values refer to the fraction of occurrence of a transition in relation to all transitions originating atthe same node Grey arrows and numbers indicate the calculated values expected if the three movements were equally likely to follow each other given the observed number ofmovements and transition strings The box size is scaled to the number of movements starts and ends respectively (N frac14 inside the boxes) Asterisks mark transitions that differedsignificantly in observed versus expected probabilities P lt 001 P lt 0001 (b) Three representative sequences of movements during song are shown For more examples oftransition strings and frequency of occurrence see Table A2

R Ullrich et al Animal Behaviour 112 (2016) 285e300 293

However this was not the case for BW and TA indicating that bothmovements seem to be more specifically related to courtshipactivity

Together our results provide quantitative evidence that thezebra finch courtship dance is coordinated temporally with court-ship song As such it could constitute an honest multimodal signalthat allows females to evaluate male fitness during mate choiceSong production depends on both peripheral components(including the lungs air sacs respiratory muscles the vocal organ(syrinx) and the upper vocal tract) and central neural control byrespiratory-vocal circuits (Schmidt ampWild 2014 Suthers Goller ampPytte 1999) In fact a previous study on zebra finches demon-strated that during song oxygen consumption increases comparedto nonsong (Franz amp Goller 2003) This could explain the observedabsence of bodily movements within motifs as a result of physicalconstraints However the study happened under the exclusion ofdance which limits its results for interpretation of the current re-sults Because dance movements are similarly subject to peripheraland central motor constraints and have to be coordinated withsong multimodal signalling could provide information about thedevelopmental history or current physical fitness of the male(Byers Hebets amp Podos 2010 Cotton Small amp Pomiankowski2006 Fuxjager Longpre Chew Fusani amp Schlinger 2013) In factdevelopmental nutritional stress does affect song learning invarious songbird species (Brumm Zollinger amp Slater 2009Buchanan Leitner Spencer Goldsmith amp Catchpole 2004Buchanan Spencer Goldsmith amp Catchpole 2003 Nowicki

Searcy amp Peters 2002 Zann amp Cash 2007) but to date dance orother motor behaviours have not been investigated in this contextIn humans developmental disturbances are also linked to deficitsin integrating speech with gestures (Iverson 2010)

The current study provides fertile ground to explore the neuralsubstrates underlying courtship dance and its integration withsong The fact that the song nucleus LMAN is required for theacoustic differences between undirected and directed song but notneeded for courtship dancing emphasizes that song and dance areindependently controlled but integrated motor behaviours (Kao ampBrainard 2006) Candidate regions for the control of the dancemovements are the motor regions in close proximity to the songcontrol nuclei (Feenders et al 2008) In male golden-collaredmanakins famous for their elaborate courtship dances volumedifferences in brain areas of males and nondancing females pointtowards the arcopallium and hippocampus as candidate controlregions (Schlinger Barske Day Fusani amp Fuxjager 2013)

Further studies in this subject are also promising because oneprominent theory of language evolution posits a gestural origin(Arbib Liebal amp Pika 2008 Armstrong Stokoe amp Wilcox 1995)This notion is supported by observations that language and actionsystems in the brain overlap (Willems Ozyuumlrek amp Hagoort 2007)Thus investigating the neural interconnection of vocalization andgesture in birds could extend the numerous parallels betweenhuman speech and birdsong (Bolhuis Okanoya amp Scharff 2010Ohms Gill Van Heijningen Beckers amp ten Cate 2010) This isparticularly interesting because human gestures are a universal

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

R Ullrich et al Animal Behaviour 112 (2016) 285e300294

feature of communication and tightly timed with speech (McNeil1992 p 1) Moreover our finding that the stroke of a hop (egwhen both feet are in the air) coincides precisely with or justbefore the introductory notes of the song is reminiscent of the factthat in people the stroke of a gesture occurs shortly before ordirectly on lsquothe prosodic stress peak of the accompanying spokenutterancersquo (McNeil 1992 p 131) Because gestures in human lan-guage are so closely associated with semantics it would also beinteresting to extend our kind of study to other behavioural con-texts such as parental-offspring interactions (Goldstein King ampWest 2003) and other areas of social learning (KatsnelsonMotro Feldman amp Lotem 2008) with an eye on the differentiallsquomeaningrsquo of same-sounddifferent-gesture combinations(OLoghlen amp Rothstein 2010)

In summary our findings provide a comprehensive analysis ofgestural signalling in male zebra finches while courting Our resultsinvite follow-up studies into the consequences and mechanisms ofmultimodal signalling in songbirds

Acknowledgments

We thank F Nottebohm H Hultsch and H Williams and twoanonymous referees for critical comments on the manuscript Weare indebted to M Weiss for statistical support For assistance withthe video recordings we thank M Kloszlig and M Gessinger Alsothanks to excellent bird care by Janett Birkenfeld We acknowledgethe support of a consortium grant of the German Federal Ministryof Education and Research (BMBF lsquoVarying Tunesrsquo 01 GQ 0963) aswell as a grant from SFB 665 Developmental Disturbances in theNervous System

Supplementary Material

Supplementary material related to this article can be found inthe online version at httpdxdoiorg101016janbehav201511012

References

Arbib M A Liebal K amp Pika S (2008) Primate vocalization gesture and theevolution of human language Current Anthropology 49(6) 1053e1076 httpdxdoiorg101086593015

Armstrong D F Stokoe W C amp Wilcox S E (1995) Gesture and the nature oflanguage Cambridge NY Cambridge University Press

Barclay S R Harding C F amp Waterman S (1992) Correlations between cate-cholamine levels and sexual behavior in male zebra finches PharmacologyBiochemistry and Behavior 41(1) 195e201

Barske J Schlinger B A Wikelski M amp Fusani L (2011 April) Female choice formale motor skills Proceedings of the Royal Society B Biological Sciences 2783523e3528 httpdxdoiorg101098rspb20110382 rspb20110382

Bates D Maechler M amp Bolker B (2012) lme4 Linear mixed-effects models usingS4 classes Retrieved from httpcranr-projectorgpackagefrac14lme4

Bee M A amp Micheyl C (2008) The lsquoCocktail Party Problemrsquo what is it How can itbe solved and why should animal behaviorists study it Journal of ComparativePsychology 122(3) 235e251 httpdxdoiorg1010370735-70361223235

Beuroohner J amp Veit F (1993) Gesangsstruktur und Formen der Fluumlgelbewegung beimStar (Sturnus vulgaris) Journal of Ornithology 134(3) 309e315

Bolhuis J J Okanoya K amp Scharff C (2010) Twitter evolution convergingmechanisms in birdsong and human speech Nature Reviews Neuroscience11(11) 747e759 httpdxdoiorg101038nrn2931

Bostwick K S (2000) Display behaviors mechanical sounds and evolutionaryrelationships of the club-winged manakin (Machaeropterus deliciosus) Auk117(2) 465e478 httpdxdoiorg1016420004-8038(2000)117[0465DBMSAE]20CO2

Brumm H Zollinger S amp Slater P (2009) Developmental stress affects songlearning but not song complexity and vocal amplitude in zebra finchesBehavioral Ecology and Sociobiology 63(9) 1387e1395 httpdxdoiorg101007s00265-009-0749-y

Buchanan K L Leitner S Spencer K A Goldsmith A R amp Catchpole C K (2004)Developmental stress selectively affects the song control nucleus HVC in thezebra finch Proceedings of the Royal Society B Biological Sciences 271(1555)2381e2386 httpdxdoiorg101098rspb20042874

Buchanan K L Spencer K A Goldsmith A R amp Catchpole C K (2003) Song as anhonest signal of past developmental stress in the European starling (Sturnusvulgaris) Proceedings of the Royal Society B Biological Sciences 270(1520)1149e1156 httpdxdoiorg101098rspb20032330

Byers J Hebets E amp Podos J (2010) Female mate choice based upon male motorperformance Animal Behaviour 79(4) 771e778 httpdxdoiorg101016janbehav201001009

Caryl P (1981) The relationship between the motivation of directed and undirectedsong in the zebra finch Zeitschrift fuumlr Tierpsychologie 57 37e50

Cooper B G amp Goller F (2004) Multimodal signals enhancement and constraintof song motor patterns by visual display Science (New York NY) 303(5657)544e546 httpdxdoiorg101126science1091099

Cooper B G amp Goller F (2006) Physiological insights into the social-context-dependent changes in the rhythm of the song motor program Journal ofNeurophysiology 95(6) 3798e3809 httpdxdoiorg101152jn011232005

Cotton S Small J amp Pomiankowski A (2006) Sexual selection and condition-dependent mate preferences Current Biology CB 16(17) R755eR765 httpdxdoiorg101016jcub200608022

Dalziell A Peters R Cockburn A Dorland A D Maisey A C amp Magrath R D(2013) Dance choreography is coordinated with song repertoire in a complexavian display Current Biology 23(12) 1132e1135 httpdxdoiorg101016jcub201305018

Dunn A M amp Zann R A (1996) Undirected song in wild zebra finch flocksEthology 102(4) 529e539 httpdxdoiorg101111j1439-03101996tb01145x

Elias D O (2006) Female preference for complexnovel signals in a spiderBehavioral Ecology 17(5) 765e771 httpdxdoiorg101093behecoarl005

Feenders G Liedvogel M Rivas M Zapka M Horita H Hara E et al (2008)Molecular mapping of movement-associated areas in the avian brain a motortheory for vocal learning origin PLoS One 3(3) e1768 httpdxdoiorg101371journalpone0001768

Fox J amp Weisberg S (2011) An R companion to applied regression Thousand OaksCA Sage Retrieved from httpscranr-projectorgwebpackagescarindexhtml

Franz M amp Goller F (2003) Respiratory patterns and oxygen consumption insinging zebra finches The Journal of Experimental Biology 206(Pt 6) 967e978httpdxdoiorg101242jeb00196

Fusani L Hutchison R E amp Hutchison J B (1997) Vocal-postural co-ordination ofa sexually dimorphic display in a monomorphic species the Barbary doveBehaviour 134(5) 321e335

Fuxjager M J Longpre K M Chew J G Fusani L amp Schlinger B A (2013) Pe-ripheral androgen receptors sustain the acrobatics and fine motor skill ofelaborate male courtship Endocrinology 154(9) 3168e3177 httpdxdoiorg101210en2013-1302

Goldin-Meadow S amp Alibali M W (2013) Gestures role in speaking learning andcreating language Annual Review of Psychology 64(c) 257e283 httpdxdoiorg101146annurev-psych-113011-143802

Goldstein M H King A P amp West M J (2003) Social interaction shapes babblingtesting parallels between birdsong and speech Proceedings of the NationalAcademy of Sciences of the United States of America 100(13) 8030e8035 httpdxdoiorg101073pnas1332441100

Hoepfner A R amp Goller F (2013) Atypical song reveals spontaneously developingcoordination between multi-modal signals in brown-headed cowbirds(Molothrus ater) PLoS One 8(6) 1e8 httpdxdoiorg101371journalpone0065525

Hothorn T Bretz F amp Westfall P (2008) Simultaneous inference in generalparametric models Biometrical Journal 50(3) 346e363

Immelmann K (1959) Experimentelle Untersuchungen uumlber die biologischeBedeutung artspezifischer Merkmale beim Zebrafinken (Taeniopygia castanotisGould) Zoologisches Jahrbuch Abteilung Fuumlr Systematik 86 435e592

Immelmann K (1969) Der Zebrafink (Taeniopygia guttata) Stuttgart GermanyFranckhsche Verlagshandlung

Iverson J M (2010) Multimodality in infancy vocal-motor and speech-gesturecoordinations in typical and atypical development Enfance Psychologie Ped-agogie Neuropsychiatrie Sociologie 2010(3) 257e274 httpdxdoiorg104074S0013754510003046

Jarvis E D Scharff C Grossman M R Ramos J A amp Nottebohm F (1998) Forwhom the bird sings context-dependent gene expression Neuron 21(4)775e788 httpdxdoiorg101016S0896-6273(00)80594-2

Kao M H amp Brainard M S (2006) Lesions of an avian basal ganglia circuit preventcontext-dependent changes to song variability Journal of Neurophysiology96(3) 1441e1455 httpdxdoiorg101152jn011382005

Katsnelson E Motro U Feldman M W amp Lotem A (2008) Early experienceaffects producerescrounger foraging tendencies in the house sparrow AnimalBehaviour 75(4) 1465e1472 httpdxdoiorg101016janbehav200709020

Kunkel P (1959) Zum Verhalten einiger Prachtfinken (Estrilidinae) Zeitschrift fuumlrTierpsychologie 16(3) 302e350

Lukianchuk K C amp Doucet S M (2014) Cooperative courtship display in long-tailed manakins Chiroxiphia linearis predictors of courtship success revealedthrough full characterization of display Journal of Ornithology 155(3) 729e743httpdxdoiorg101007s10336-014-1059-3

McNeil D (1992) Hand and mind What gestures reveal about thought What gesturesreveal about Chicago IL The University of Chicago Press

Moorman S amp Bolhuis J J (2013) Behavioral similarities between birdsong andspoken language In J J Bolhuis amp M Everaert (Eds) Birdsong speech and

R Ullrich et al Animal Behaviour 112 (2016) 285e300 295

language exploring the evolution of mind and brain (pp 111e123) CambridgeMA MIT Press

Morris D (1954) The reproductive behaviour of the Zebra Finch (Poephila guttata)with special reference to pseudofemale behaviour and displacement activitiesBehaviour 6(4) 271e322

Morris D (1957) lsquoTypical Intensityrsquo and its relation to the problem of ritualisationBehaviour 11(1) 1e12

Nowicki S Searcy W A amp Peters S (2002) Brain development song learning andmate choice in birds a review and experimental test of the lsquonutritional stresshypothesisrsquo Journal of Comparative Physiology A Neuroethology Sensory Neuraland Behavioral Physiology 188(11e12) 1003e1014 httpdxdoiorg101007s00359-002-0361-3

Ohms V R Gill A Van Heijningen C A Beckers G J amp ten Cate C (2010) Zebrafinches exhibit speaker-independent phonetic perception of human speechProceedings of the Royal Society B Biological Sciences 277(1684) 1003e1009httpdxdoiorg101098rspb20091788

OLoghlen A L amp Rothstein S I (2010) Multimodal signalling in a songbird maleaudiovisual displays vary significantly by social context in brown-headedcowbirds Animal Behaviour 79(6) 1285e1292 httpdxdoiorg101016janbehav201003001

OLoghlen A L amp Rothstein S I (2012) When less is best female brown-headedcowbirds prefer less intense male displays PLoS One 7(5) 1e8 httpdxdoiorg101371journalpone0036130

Pinheiro J Bates D DebRoy S Sarkar D amp R Development Core Team R (2011)nlme Linear and nonlinear mixed effects models Retrieved from httpcranr-projectorgpackagefrac14nlme

R Development Core Team R (2011) R A language and environment for statisticalcomputing Vienna Austria R Foundation for Statistical Computing Retrievedfrom httpwwwr-projectorg

Rauceo S Harding C F Maldonado A Gaysinkaya L Tulloch I amp Rodriguez E(2008) Dopaminergic modulation of reproductive behavior and activity in malezebra finches Behavioural Brain Research 187(1) 133e139 httpdxdoiorg101016jbbr200709003

Riebel K (2009) Song and female mate choice in zebra finches a review Advancesin the Study of Behavior 40 197e238 httpdxdoiorg101016S0065-3454(09)40006-8

Ruploh T Bischof H-J amp Engelhardt N (2012) Adolescent social environmentshapes sexual and aggressive behaviour of adult male zebra finches (Taenio-pygia guttata) Behavioral Ecology and Sociobiology 67(2) 175e184 httpdxdoiorg101007s00265-012-1436-y

Schlinger B A Barske J Day L Fusani L amp Fuxjager M J (2013) Hormones andthe neuromuscular control of courtship in the golden-collared manakin(Manacus vitellinus) Frontiers in Neuroendocrinology 34(3) 143e156 httpdxdoiorg101016jyfrne201304001

Table A1Camera and recording specifications for experiment A B C

Experiment Camera

AIndoor2010

Panasonic WV-CP500G 30 fps 720576 pixel resolution perspective to

BOutdoor2011

Canon LEGRIA FS200 Camcorder 25 fps 720576 pixel resolution perspe

CIndoor2013

Microsoft LifeCam VX-700 (USB) 30 fps 640480 pixel resolution perspeImaging Source FireWire CCD Color DFK 21AF04 60 fps 640 480 pixelperspective side view

Schmidt M F amp Wild J M (2014) The respiratory-vocal system of songbirdsanatomy physiology and neural control Progress in Brain Research 212297e335 httpdxdoiorg101016B978-0-444-63488-700015-X

Slater P J B Eales L A amp Clayton N S (1988) Song learning in zebra finchesprogress and prospects In Advances in the study of behavior (Vol 18 pp 1e34)London UK Academic Press

Soma M amp Garamszegi L Z (2015) Evolution of courtship display in Estrildidfinches dance in relation to female song and plumage ornamentation Frontiersin Ecology and Evolution 3(February) 1e11 httpdxdoiorg103389fevo201500004

Soma M amp Mori C (2015) The songbird as a percussionist Syntactic Rules fornon-vocal sound and song production in java sparrows PLoS One 10(5)e0124876 httpdxdoiorg101371journalpone0124876

Sossinka R amp Beuroohner J (1980) Song types in the zebra finch Poephila guttatacastanotis Zeitschrift fuumlr Tierpsychologie 53(2) 123e132

Suthers R A Goller F amp Pytte C (1999) The neuromuscular control of birdsongPhilosophical Transactions of the Royal Society of London Series B BiologicalSciences 354(1385) 927e939 httpdxdoiorg101098rstb19990444

Taylor R C Klein B A Stein J amp Ryan M J (2011) Multimodal signal variation inspace and time how important is matching a signal with its signaler TheJournal of Experimental Biology 214(Pt 5) 815e820 httpdxdoiorg101242jeb043638

Willems R M Ozyuumlrek A amp Hagoort P (2007) When language meets action theneural integration of gesture and speech Cerebral Cortex (New York NY) 17(10)2322e2333 httpdxdoiorg101093cercorbhl141

Williams H (2001) Choreography of song dance and beak movements in the zebrafinch (Taeniopygia guttata) The Journal of Experimental Biology 204(20)3497e3506

Woolley S C amp Doupe A J (2008) Social contexteinduced song variation affectsfemale behavior and gene expression PLoS Biology 6(3) e62 httpdxdoiorg101371journalpbio0060062

Zann R A (1996) The zebra finch A synthesis of field and laboratory studies OxfordUK Oxford University Press

Zann R A amp Cash E (2007) Developmental stress impairs song complexity butnot learning accuracy in non-domesticated zebra finches (Taeniopygia guttata)Behavioral Ecology and Sociobiology 62(3) 391e400 httpdxdoiorg101007s00265-007-0467-2

APPENDIX

Methods

Recording software Microphone

p view Noldus Recorder Sennheiser ME80K3Uthornpreamplifiervivanco MA222

ctive side view Sennheiser ME80K3U

ctive top viewresolution

Noldus MediaRecorder 2

Sennheiser ME80K3UthornConrad USB soundcard 71

R Ullrich et al Animal Behaviour 112 (2016) 285e300296

Behaviour definitions audio and video analysis

BW

1 2 3 4 5 6

TA

TA

Hop

Figure A1 Still frames from videotaped material (30 fps) of male 3641 illustrating key moments of the three song-associated body movements BW TA (filmed from the front andabove) and hops The female is visible behind the window in the far right The top row illustrates six of 19 positions in a BW sequence that lasted 570 ms in total Frame 1 inceptionof the movement frames 2 and 3 lowering of the head frame 4 lsquostrokersquo which depicts the lowest head position frame 5 head lifting 6 completion of poststroke phase The timestamps of frames 1 and 6 were used to mark the beginning and end of the BW The time stamp of frame 4 served to mark the BW itself as a point event The second and third rowsillustrate six of 21 frames in a TA sequence lasting 630 ms in total Frame 1 inception of the movement frames 2 to 5 the body axis is turning towards the right frame 4 depicts thestroke of a TA when the tail crosses the perch and both feet are displaced from the perch frame 6 depicts the completion of the TA The time stamps of frames 1 and 6 were used tomark the beginning and end of the TA The stroke was used to mark the TA as a point event The stroke of a TA was also scored as a hop The bottom row shows six of 10 frames in ahop sequence covering a total of 300 ms Only the stroke of the sequence when both feet were off the perch was scored for hops (frame 4)

For one experiment (Nfrac1410) we included time stamps for the 2 stime window before the onset of the introductory note for theintroductory note itself and for the onset and end of the first motifnote However when analysing the frequency of the movementbetween the single segments we could not find any significantdifferenceWe therefore decided tomerge thementioned segmentsto an overall segment called lsquostartrsquo We did the same for both of theother categories and ended up with three categories lsquostartrsquolsquocentrersquo lsquoendrsquo

Hopping and calling associated by chanceWe focused only on calls and hops that occurred before and after

songs not during songs (ie excluding song itself and 2 s before andafter) To do so wemeasured for each bird the average call durationof 10 calls per 5 min video produced during lsquononsongrsquo in four to 10videos resulting in 40e100 calls per bird The average call lengthwas determined empirically to be 75 ms (SD plusmn 26 ms) Hop dura-tion was determined by measuring three randomly chosen hopsfrom one bird using a series of video still images which yielded aduration of 300e333 ms To avoid overestimation of hops and callscoinciding we shortened the duration of hopping to 225 ms toreceive more conservative results for both calculations the realobservation and the following Monte Carlo simulation We thus

counted hops and calls as lsquooverlappingrsquowhen they occurred withina 300 ms time window (225 ms estimated hop duration thorn 75 mscall duration) For each bird we used the actual number of hops andcalls and distributed them randomly over time for 1000 times Notethat on one side every turn-around included a hop but for thespecific analyis of hopping movements we excluded these Wecounted the number of times hopping and calling coincided as aresult of the random distribution A mean value from all 1000randomizations was used to compare these results to the observedvalues

Calculation of the expected transition ratios during songTo determine whether movement sequences differed from

chance we analysed the transition frequencies between move-ments and then calculated the transition ratios that would be ex-pected if the movement sequences were in random order (giventhe observed total numbers of movements and observed transitionstrings)

Because we only considered transition probabilities betweentwo events (movements or startend of a string) independent ofother preceding events the probability of a transition betweenthese two events depends only on the relative frequency of thesecond event Thus (1) the expected probabilities for the transitionsin our sequence analysis from start to TA (or to BW or to hop) were

N = 20

P = 0008

P = 0025

R2 = 025

R2 = 033

(a)

(b)

400

200

100

0

100

No

of

BW

300

150

o o

f TA

R Ullrich et al Animal Behaviour 112 (2016) 285e300 297

calculated by dividing the total number of TA (or BW or hopsrespectively) by the sum of all three movements yielding therelative frequency of the respective movement (Table A3 column1) (2) To calculate the expected probability that a TA (or BWor hop)ends a transition string we had to take string length into accountsince longer strings result in fewer endings We thus obtained theprobability of any movement ending a transition string by dividingone by the average observed string length (1433 frac14 023) Putdifferently this value is the proportion of transitions from onemovement to the end of a string in relation to all transitions (bothfrom one movement to another movement and from a movementto an end Table A3 fourth row) (3) All movements not terminatinga string have a probability of transitioning to a TA (or BW or hop)equal to the relative frequency of the respective movement (see 1)Therefore we calculated the expected probabilities of the transi-tions from one movement to another as the product of the relativefrequency of the second movement and 1 minus the probability ofthe first movement ending a string (1e023 frac14 077 Table A3 col-umns 2e4)

Statistical Analysis data transformationWe chose the cube root to transform non-normal data because

applying the square root did not lead to a normal distribution insome cases and log transform was not suitable due to the presenceof several zero values in some data sets

Results

N = 20

P = 092

N = 10

R2 = 00012(c)

50

90

80

70

60

50

40

30

10 20 30

No of bouts

No

of

hop

s

40 50 60 70 80

N

Figure A2 Number of (a) BW (b) TA and (c) hops in relation to number of bouts sungSee text for statistics

0 01

005005

01

01

015

015

005

01

01502

02 03 04 05 06 07 0 005 01 015 02 025 0 01 02 03 04 05 06

No

of

BW

du

rin

g n

onso

ng

s

No

of

TA d

uri

ng

non

son

gs

No

of

hop

s d

uri

ng

non

son

gsR2 = 0124 R2 = 007 R2 = 0586

P = 013 P = 026 P = 001

(a) (b) (c)

No of TA during songs No of hops during songsNo of BW during songs

N = 10N = 20N = 20

Figure A3 Correlations of body movements between song and nonsong (a) BW (b) TA and (c) hops Pearson product moment correlation BW song versus nonsong t18 frac14 16P lt 013 TA song versus nonsong t18 frac14 116 P frac14 026 hop song versus nonsong t8 frac14 336 P lt 0001

ObservedExpected

200

150

100

50

0HH BT TB

Observed gt Expected

Nu

mbe

r of

tra

nsi

tion

s

Transition type

sH BB Be Te TT BH HB

Observed lt Expected

sB HT TH HesT

Figure A4 Differences between observed and expected transition frequencies during song Observed absolute number of transitions observed during song of 10 birds (black)expected number expected if the three movements were equally likely to follow each other given the observed number of all movements and transition strings (grey) The bars areordered by relative difference between observed and expected number and grouped as O gt E (left) and O lt E (right) B beak wipe H hop T turn-around s start of a transitionstring e end of a transition string

R Ullrich et al Animal Behaviour 112 (2016) 285e300298

SongNonsong

04

02

01

02 3 4 5 6 7 8 9 10

Transition string length

Rel

ativ

e fr

equ

ency

11 12 13 14 15 16 17 18 19

03

Figure A6 Transition string length during song (dark bars) and nonsong (light bars) Values in the histogram are given as frequencies relative to the total number of transitionsduring song and nonsong respectively A transition length of 2 represents a transition between two movements 3 frac14 three movements etc

1

05

0

ndash05O

bser

ved

rat

io -

exp

ecte

d r

atio

ndash1BB BH BT HB HH

Transition type

HT TB TH TT

Figure A5 Expected transition ratios subtracted from observed transition ratios during song Transition probabilities expected if the three movements were equally likely to followeach other subtracted from the observed ratios of 10 birds (black dots) and medians (horizontal lines) for the nine transition types B beak wipe H hop T turn-around Asterisksmark the transition types where observed ratios differed significantly from expected ones P lt 001 P lt 0001 See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300 299

Table A2List of the most frequently observed movement sequences

Transitionstring

Frequency of occurrence as a string or as part of a longerstring

Frequency of occurrence as astring

Stringlength

Format indicating incorporatedmovements

BTB 42 4 3 BW amp TAHHB 42 0 3 Hop amp TAHBH 26 0 3 BW amp hopTHH 24 4 3 All threeTBT 22 2 3TBB 22 1 3HHT 21 3 3BHH 20 0 3HHHB 20 2 4HHBH 15 0 4BTBB 14 1 4HHHT 13 2 4TBBB 12 2 4THHH 12 2 4BTBT 12 1 4HHBB 11 1 4HHHHT 10 3 5HHHHB 8 0 5HHHBB 7 1 5TBBBB 7 0 5THHHH 6 2 5HTHHH 6 1 5BTBBB 6 0 5BBTBB 6 0 5TBBBBB 6 1 6BTBBBB 5 1 6HHHHTH 5 1 6HHHHHB 4 1 6HHHHHT 4 1 6HHHBHB 4 0 6HHBBTB 4 0 6HBHHBH 4 0 6BTBBBBB 4 0 7HBHHBHH 4 0 7HHHTHHH 4 0 7HHHHBHB 3 1 7TBBBBBB 3 0 7BBTBBBB 3 0 7HHBBTBB 3 0 7HTHHHHH 3 0 7

Strings are ordered by their frequency of appearing either as a whole transition string or as part of a longer transition string during song of 10 birds Included in this table arethe eight most frequent strings that contain at least two types of movements for string lengths of three to seven movements each Romanbolditalicsunderlining indicatewhich of the movements are included in each string B beak wipe H hop T turn-around

Table A3Calculation of expected transition probabilities

Probability of transition From start From TA From BW From hop

To TA nTAnALL 077(nTAnALL) 077(nTAnALL) 077(nTAnALL)To BW nBWnALL 077(nBWnALL) 077(nBWnALL) 077(nBWnALL)To hop nHopnALL 077(nHopnALL) 077(nHopnALL) 077(nHopnALL)To end e 023 023 023Sum 1 1 1 1

nTA nBW and nHop are the total number of turn-arounds beak wipes and hops as part of transitions respectively nALL frac14 nTA thorn nBW thorn nHop Note that the probabilities forall transitions starting at a specific event sum to 1

R Ullrich et al Animal Behaviour 112 (2016) 285e300300

• Waltzing Taeniopygia integration of courtship song and dance in the domesticated Australian zebra finch
• • Methods
  • • Subjects
    • Recording
    • Behaviour Definitions Audio and Video Analysis
    • Ethical Note
    • • Results
      • • Body Movements were Associated with Song
        • During Song BW but not TA were Performed Faster
        • BW and TA were Correlated with Amount of Song
        • Hop Rates During Song Correlated with those Outside Song
        • During Song Numbers of BW and TA were Tightly Related
        • Hops Coincided with Particular Notes
        • Behaviour Transition Ratios Differed from those Expected
        • • Discussion
          • Acknowledgments
          • Supplementary Material
          • References
          • Appendix
          • • Methods
            • • Behaviour definitions audio and video analysis
              • Hopping and calling associated by chance
              • Calculation of the expected transition ratios during song
              • Statistical Analysis data transformation
              • • Results

N = 20

P = 0008

P = 0025

R2 = 025

R2 = 033

(a)

(b)

400

200

100

0

100

No

of

BW

300

150

o o

f TA

R Ullrich et al Animal Behaviour 112 (2016) 285e300 297

calculated by dividing the total number of TA (or BW or hopsrespectively) by the sum of all three movements yielding therelative frequency of the respective movement (Table A3 column1) (2) To calculate the expected probability that a TA (or BWor hop)ends a transition string we had to take string length into accountsince longer strings result in fewer endings We thus obtained theprobability of any movement ending a transition string by dividingone by the average observed string length (1433 frac14 023) Putdifferently this value is the proportion of transitions from onemovement to the end of a string in relation to all transitions (bothfrom one movement to another movement and from a movementto an end Table A3 fourth row) (3) All movements not terminatinga string have a probability of transitioning to a TA (or BW or hop)equal to the relative frequency of the respective movement (see 1)Therefore we calculated the expected probabilities of the transi-tions from one movement to another as the product of the relativefrequency of the second movement and 1 minus the probability ofthe first movement ending a string (1e023 frac14 077 Table A3 col-umns 2e4)

Statistical Analysis data transformationWe chose the cube root to transform non-normal data because

applying the square root did not lead to a normal distribution insome cases and log transform was not suitable due to the presenceof several zero values in some data sets

Results

N = 20

P = 092

N = 10

R2 = 00012(c)

50

90

80

70

60

50

40

30

10 20 30

No of bouts

No

of

hop

s

40 50 60 70 80

N

Figure A2 Number of (a) BW (b) TA and (c) hops in relation to number of bouts sungSee text for statistics

0 01

005005

01

01

015

015

005

01

01502

02 03 04 05 06 07 0 005 01 015 02 025 0 01 02 03 04 05 06

No

of

BW

du

rin

g n

onso

ng

s

No

of

TA d

uri

ng

non

son

gs

No

of

hop

s d

uri

ng

non

son

gsR2 = 0124 R2 = 007 R2 = 0586

P = 013 P = 026 P = 001

(a) (b) (c)

No of TA during songs No of hops during songsNo of BW during songs

N = 10N = 20N = 20

Figure A3 Correlations of body movements between song and nonsong (a) BW (b) TA and (c) hops Pearson product moment correlation BW song versus nonsong t18 frac14 16P lt 013 TA song versus nonsong t18 frac14 116 P frac14 026 hop song versus nonsong t8 frac14 336 P lt 0001

ObservedExpected

200

150

100

50

0HH BT TB

Observed gt Expected

Nu

mbe

r of

tra

nsi

tion

s

Transition type

sH BB Be Te TT BH HB

Observed lt Expected

sB HT TH HesT

Figure A4 Differences between observed and expected transition frequencies during song Observed absolute number of transitions observed during song of 10 birds (black)expected number expected if the three movements were equally likely to follow each other given the observed number of all movements and transition strings (grey) The bars areordered by relative difference between observed and expected number and grouped as O gt E (left) and O lt E (right) B beak wipe H hop T turn-around s start of a transitionstring e end of a transition string

R Ullrich et al Animal Behaviour 112 (2016) 285e300298

SongNonsong

04

02

01

02 3 4 5 6 7 8 9 10

Transition string length

Rel

ativ

e fr

equ

ency

11 12 13 14 15 16 17 18 19

03

Figure A6 Transition string length during song (dark bars) and nonsong (light bars) Values in the histogram are given as frequencies relative to the total number of transitionsduring song and nonsong respectively A transition length of 2 represents a transition between two movements 3 frac14 three movements etc

1

05

0

ndash05O

bser

ved

rat

io -

exp

ecte

d r

atio

ndash1BB BH BT HB HH

Transition type

HT TB TH TT

Figure A5 Expected transition ratios subtracted from observed transition ratios during song Transition probabilities expected if the three movements were equally likely to followeach other subtracted from the observed ratios of 10 birds (black dots) and medians (horizontal lines) for the nine transition types B beak wipe H hop T turn-around Asterisksmark the transition types where observed ratios differed significantly from expected ones P lt 001 P lt 0001 See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300 299

Table A2List of the most frequently observed movement sequences

Transitionstring

Frequency of occurrence as a string or as part of a longerstring

Frequency of occurrence as astring

Stringlength

Format indicating incorporatedmovements

BTB 42 4 3 BW amp TAHHB 42 0 3 Hop amp TAHBH 26 0 3 BW amp hopTHH 24 4 3 All threeTBT 22 2 3TBB 22 1 3HHT 21 3 3BHH 20 0 3HHHB 20 2 4HHBH 15 0 4BTBB 14 1 4HHHT 13 2 4TBBB 12 2 4THHH 12 2 4BTBT 12 1 4HHBB 11 1 4HHHHT 10 3 5HHHHB 8 0 5HHHBB 7 1 5TBBBB 7 0 5THHHH 6 2 5HTHHH 6 1 5BTBBB 6 0 5BBTBB 6 0 5TBBBBB 6 1 6BTBBBB 5 1 6HHHHTH 5 1 6HHHHHB 4 1 6HHHHHT 4 1 6HHHBHB 4 0 6HHBBTB 4 0 6HBHHBH 4 0 6BTBBBBB 4 0 7HBHHBHH 4 0 7HHHTHHH 4 0 7HHHHBHB 3 1 7TBBBBBB 3 0 7BBTBBBB 3 0 7HHBBTBB 3 0 7HTHHHHH 3 0 7

Strings are ordered by their frequency of appearing either as a whole transition string or as part of a longer transition string during song of 10 birds Included in this table arethe eight most frequent strings that contain at least two types of movements for string lengths of three to seven movements each Romanbolditalicsunderlining indicatewhich of the movements are included in each string B beak wipe H hop T turn-around

Table A3Calculation of expected transition probabilities

Probability of transition From start From TA From BW From hop

To TA nTAnALL 077(nTAnALL) 077(nTAnALL) 077(nTAnALL)To BW nBWnALL 077(nBWnALL) 077(nBWnALL) 077(nBWnALL)To hop nHopnALL 077(nHopnALL) 077(nHopnALL) 077(nHopnALL)To end e 023 023 023Sum 1 1 1 1

nTA nBW and nHop are the total number of turn-arounds beak wipes and hops as part of transitions respectively nALL frac14 nTA thorn nBW thorn nHop Note that the probabilities forall transitions starting at a specific event sum to 1

R Ullrich et al Animal Behaviour 112 (2016) 285e300300

• Waltzing Taeniopygia integration of courtship song and dance in the domesticated Australian zebra finch
• • Methods
  • • Subjects
    • Recording
    • Behaviour Definitions Audio and Video Analysis
    • Ethical Note
    • • Results
      • • Body Movements were Associated with Song
        • During Song BW but not TA were Performed Faster
        • BW and TA were Correlated with Amount of Song
        • Hop Rates During Song Correlated with those Outside Song
        • During Song Numbers of BW and TA were Tightly Related
        • Hops Coincided with Particular Notes
        • Behaviour Transition Ratios Differed from those Expected
        • • Discussion
          • Acknowledgments
          • Supplementary Material
          • References
          • Appendix
          • • Methods
            • • Behaviour definitions audio and video analysis
              • Hopping and calling associated by chance
              • Calculation of the expected transition ratios during song
              • Statistical Analysis data transformation
              • • Results

0 01

005005

01

01

015

015

005

01

01502

02 03 04 05 06 07 0 005 01 015 02 025 0 01 02 03 04 05 06

No

of

BW

du

rin

g n

onso

ng

s

No

of

TA d

uri

ng

non

son

gs

No

of

hop

s d

uri

ng

non

son

gsR2 = 0124 R2 = 007 R2 = 0586

P = 013 P = 026 P = 001

(a) (b) (c)

No of TA during songs No of hops during songsNo of BW during songs

N = 10N = 20N = 20

Figure A3 Correlations of body movements between song and nonsong (a) BW (b) TA and (c) hops Pearson product moment correlation BW song versus nonsong t18 frac14 16P lt 013 TA song versus nonsong t18 frac14 116 P frac14 026 hop song versus nonsong t8 frac14 336 P lt 0001

ObservedExpected

200

150

100

50

0HH BT TB

Observed gt Expected

Nu

mbe

r of

tra

nsi

tion

s

Transition type

sH BB Be Te TT BH HB

Observed lt Expected

sB HT TH HesT

Figure A4 Differences between observed and expected transition frequencies during song Observed absolute number of transitions observed during song of 10 birds (black)expected number expected if the three movements were equally likely to follow each other given the observed number of all movements and transition strings (grey) The bars areordered by relative difference between observed and expected number and grouped as O gt E (left) and O lt E (right) B beak wipe H hop T turn-around s start of a transitionstring e end of a transition string

R Ullrich et al Animal Behaviour 112 (2016) 285e300298

SongNonsong

04

02

01

02 3 4 5 6 7 8 9 10

Transition string length

Rel

ativ

e fr

equ

ency

11 12 13 14 15 16 17 18 19

03

Figure A6 Transition string length during song (dark bars) and nonsong (light bars) Values in the histogram are given as frequencies relative to the total number of transitionsduring song and nonsong respectively A transition length of 2 represents a transition between two movements 3 frac14 three movements etc

1

05

0

ndash05O

bser

ved

rat

io -

exp

ecte

d r

atio

ndash1BB BH BT HB HH

Transition type

HT TB TH TT

Figure A5 Expected transition ratios subtracted from observed transition ratios during song Transition probabilities expected if the three movements were equally likely to followeach other subtracted from the observed ratios of 10 birds (black dots) and medians (horizontal lines) for the nine transition types B beak wipe H hop T turn-around Asterisksmark the transition types where observed ratios differed significantly from expected ones P lt 001 P lt 0001 See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300 299

Table A2List of the most frequently observed movement sequences

Transitionstring

Frequency of occurrence as a string or as part of a longerstring

Frequency of occurrence as astring

Stringlength

Format indicating incorporatedmovements

BTB 42 4 3 BW amp TAHHB 42 0 3 Hop amp TAHBH 26 0 3 BW amp hopTHH 24 4 3 All threeTBT 22 2 3TBB 22 1 3HHT 21 3 3BHH 20 0 3HHHB 20 2 4HHBH 15 0 4BTBB 14 1 4HHHT 13 2 4TBBB 12 2 4THHH 12 2 4BTBT 12 1 4HHBB 11 1 4HHHHT 10 3 5HHHHB 8 0 5HHHBB 7 1 5TBBBB 7 0 5THHHH 6 2 5HTHHH 6 1 5BTBBB 6 0 5BBTBB 6 0 5TBBBBB 6 1 6BTBBBB 5 1 6HHHHTH 5 1 6HHHHHB 4 1 6HHHHHT 4 1 6HHHBHB 4 0 6HHBBTB 4 0 6HBHHBH 4 0 6BTBBBBB 4 0 7HBHHBHH 4 0 7HHHTHHH 4 0 7HHHHBHB 3 1 7TBBBBBB 3 0 7BBTBBBB 3 0 7HHBBTBB 3 0 7HTHHHHH 3 0 7

Strings are ordered by their frequency of appearing either as a whole transition string or as part of a longer transition string during song of 10 birds Included in this table arethe eight most frequent strings that contain at least two types of movements for string lengths of three to seven movements each Romanbolditalicsunderlining indicatewhich of the movements are included in each string B beak wipe H hop T turn-around

Table A3Calculation of expected transition probabilities

Probability of transition From start From TA From BW From hop

To TA nTAnALL 077(nTAnALL) 077(nTAnALL) 077(nTAnALL)To BW nBWnALL 077(nBWnALL) 077(nBWnALL) 077(nBWnALL)To hop nHopnALL 077(nHopnALL) 077(nHopnALL) 077(nHopnALL)To end e 023 023 023Sum 1 1 1 1

nTA nBW and nHop are the total number of turn-arounds beak wipes and hops as part of transitions respectively nALL frac14 nTA thorn nBW thorn nHop Note that the probabilities forall transitions starting at a specific event sum to 1

R Ullrich et al Animal Behaviour 112 (2016) 285e300300

• Waltzing Taeniopygia integration of courtship song and dance in the domesticated Australian zebra finch
• • Methods
  • • Subjects
    • Recording
    • Behaviour Definitions Audio and Video Analysis
    • Ethical Note
    • • Results
      • • Body Movements were Associated with Song
        • During Song BW but not TA were Performed Faster
        • BW and TA were Correlated with Amount of Song
        • Hop Rates During Song Correlated with those Outside Song
        • During Song Numbers of BW and TA were Tightly Related
        • Hops Coincided with Particular Notes
        • Behaviour Transition Ratios Differed from those Expected
        • • Discussion
          • Acknowledgments
          • Supplementary Material
          • References
          • Appendix
          • • Methods
            • • Behaviour definitions audio and video analysis
              • Hopping and calling associated by chance
              • Calculation of the expected transition ratios during song
              • Statistical Analysis data transformation
              • • Results

SongNonsong

04

02

01

02 3 4 5 6 7 8 9 10

Transition string length

Rel

ativ

e fr

equ

ency

11 12 13 14 15 16 17 18 19

03

Figure A6 Transition string length during song (dark bars) and nonsong (light bars) Values in the histogram are given as frequencies relative to the total number of transitionsduring song and nonsong respectively A transition length of 2 represents a transition between two movements 3 frac14 three movements etc

1

05

0

ndash05O

bser

ved

rat

io -

exp

ecte

d r

atio

ndash1BB BH BT HB HH

Transition type

HT TB TH TT

Figure A5 Expected transition ratios subtracted from observed transition ratios during song Transition probabilities expected if the three movements were equally likely to followeach other subtracted from the observed ratios of 10 birds (black dots) and medians (horizontal lines) for the nine transition types B beak wipe H hop T turn-around Asterisksmark the transition types where observed ratios differed significantly from expected ones P lt 001 P lt 0001 See text for statistics

R Ullrich et al Animal Behaviour 112 (2016) 285e300 299

Table A2List of the most frequently observed movement sequences

Transitionstring

Frequency of occurrence as a string or as part of a longerstring

Frequency of occurrence as astring

Stringlength

Format indicating incorporatedmovements

BTB 42 4 3 BW amp TAHHB 42 0 3 Hop amp TAHBH 26 0 3 BW amp hopTHH 24 4 3 All threeTBT 22 2 3TBB 22 1 3HHT 21 3 3BHH 20 0 3HHHB 20 2 4HHBH 15 0 4BTBB 14 1 4HHHT 13 2 4TBBB 12 2 4THHH 12 2 4BTBT 12 1 4HHBB 11 1 4HHHHT 10 3 5HHHHB 8 0 5HHHBB 7 1 5TBBBB 7 0 5THHHH 6 2 5HTHHH 6 1 5BTBBB 6 0 5BBTBB 6 0 5TBBBBB 6 1 6BTBBBB 5 1 6HHHHTH 5 1 6HHHHHB 4 1 6HHHHHT 4 1 6HHHBHB 4 0 6HHBBTB 4 0 6HBHHBH 4 0 6BTBBBBB 4 0 7HBHHBHH 4 0 7HHHTHHH 4 0 7HHHHBHB 3 1 7TBBBBBB 3 0 7BBTBBBB 3 0 7HHBBTBB 3 0 7HTHHHHH 3 0 7

Strings are ordered by their frequency of appearing either as a whole transition string or as part of a longer transition string during song of 10 birds Included in this table arethe eight most frequent strings that contain at least two types of movements for string lengths of three to seven movements each Romanbolditalicsunderlining indicatewhich of the movements are included in each string B beak wipe H hop T turn-around

Table A3Calculation of expected transition probabilities

Probability of transition From start From TA From BW From hop

To TA nTAnALL 077(nTAnALL) 077(nTAnALL) 077(nTAnALL)To BW nBWnALL 077(nBWnALL) 077(nBWnALL) 077(nBWnALL)To hop nHopnALL 077(nHopnALL) 077(nHopnALL) 077(nHopnALL)To end e 023 023 023Sum 1 1 1 1

nTA nBW and nHop are the total number of turn-arounds beak wipes and hops as part of transitions respectively nALL frac14 nTA thorn nBW thorn nHop Note that the probabilities forall transitions starting at a specific event sum to 1

R Ullrich et al Animal Behaviour 112 (2016) 285e300300

• Waltzing Taeniopygia integration of courtship song and dance in the domesticated Australian zebra finch
• • Methods
  • • Subjects
    • Recording
    • Behaviour Definitions Audio and Video Analysis
    • Ethical Note
    • • Results
      • • Body Movements were Associated with Song
        • During Song BW but not TA were Performed Faster
        • BW and TA were Correlated with Amount of Song
        • Hop Rates During Song Correlated with those Outside Song
        • During Song Numbers of BW and TA were Tightly Related
        • Hops Coincided with Particular Notes
        • Behaviour Transition Ratios Differed from those Expected
        • • Discussion
          • Acknowledgments
          • Supplementary Material
          • References
          • Appendix
          • • Methods
            • • Behaviour definitions audio and video analysis
              • Hopping and calling associated by chance
              • Calculation of the expected transition ratios during song
              • Statistical Analysis data transformation
              • • Results

Table A2List of the most frequently observed movement sequences

Transitionstring

Frequency of occurrence as a string or as part of a longerstring

Frequency of occurrence as astring

Stringlength

Format indicating incorporatedmovements

BTB 42 4 3 BW amp TAHHB 42 0 3 Hop amp TAHBH 26 0 3 BW amp hopTHH 24 4 3 All threeTBT 22 2 3TBB 22 1 3HHT 21 3 3BHH 20 0 3HHHB 20 2 4HHBH 15 0 4BTBB 14 1 4HHHT 13 2 4TBBB 12 2 4THHH 12 2 4BTBT 12 1 4HHBB 11 1 4HHHHT 10 3 5HHHHB 8 0 5HHHBB 7 1 5TBBBB 7 0 5THHHH 6 2 5HTHHH 6 1 5BTBBB 6 0 5BBTBB 6 0 5TBBBBB 6 1 6BTBBBB 5 1 6HHHHTH 5 1 6HHHHHB 4 1 6HHHHHT 4 1 6HHHBHB 4 0 6HHBBTB 4 0 6HBHHBH 4 0 6BTBBBBB 4 0 7HBHHBHH 4 0 7HHHTHHH 4 0 7HHHHBHB 3 1 7TBBBBBB 3 0 7BBTBBBB 3 0 7HHBBTBB 3 0 7HTHHHHH 3 0 7

Strings are ordered by their frequency of appearing either as a whole transition string or as part of a longer transition string during song of 10 birds Included in this table arethe eight most frequent strings that contain at least two types of movements for string lengths of three to seven movements each Romanbolditalicsunderlining indicatewhich of the movements are included in each string B beak wipe H hop T turn-around

Table A3Calculation of expected transition probabilities

Probability of transition From start From TA From BW From hop

To TA nTAnALL 077(nTAnALL) 077(nTAnALL) 077(nTAnALL)To BW nBWnALL 077(nBWnALL) 077(nBWnALL) 077(nBWnALL)To hop nHopnALL 077(nHopnALL) 077(nHopnALL) 077(nHopnALL)To end e 023 023 023Sum 1 1 1 1

nTA nBW and nHop are the total number of turn-arounds beak wipes and hops as part of transitions respectively nALL frac14 nTA thorn nBW thorn nHop Note that the probabilities forall transitions starting at a specific event sum to 1

R Ullrich et al Animal Behaviour 112 (2016) 285e300300

• Waltzing Taeniopygia integration of courtship song and dance in the domesticated Australian zebra finch
• • Methods
  • • Subjects
    • Recording
    • Behaviour Definitions Audio and Video Analysis
    • Ethical Note
    • • Results
      • • Body Movements were Associated with Song
        • During Song BW but not TA were Performed Faster
        • BW and TA were Correlated with Amount of Song
        • Hop Rates During Song Correlated with those Outside Song
        • During Song Numbers of BW and TA were Tightly Related
        • Hops Coincided with Particular Notes
        • Behaviour Transition Ratios Differed from those Expected
        • • Discussion
          • Acknowledgments
          • Supplementary Material
          • References
          • Appendix
          • • Methods
            • • Behaviour definitions audio and video analysis
              • Hopping and calling associated by chance
              • Calculation of the expected transition ratios during song
              • Statistical Analysis data transformation
              • • Results