Why might it be important to learn more

about loon music?

Jay Mager Department of Biological & Allied Health Sciences Ohio Northern University Ada, Ohio 45810 j-mager@onu.edu

Charles Walcott Department of Neurobiology & Behavior Cornell University Ithaca, New York 14853 cw38@cornell.edu

A

B Benefit

Net Benefit A = 100

Net Benefit B = 70

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A

B

Benefit Cost

Net Benefit A = 100 - 80 = 20

Net Benefit B = 70 - 20 = 50

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?

Dan Salsbury

W. Piper

Nathan Banfield

Yodel Acoustic Structure:

The yodel as an aggressive threat signal:

Given by only male Great Northern Divers (Gavia immer)

Given primarily to conspecific flyovers & intrusions

Given when probability of physical confrontation is high, & given in “vulture posture” during close confrontations

Given most frequently upon return to breeding territories & when chicks are about to hatch

Dan Salsbury

Yodel Acoustic Structure: Fighting Ability

(Mager et al. 2007, in prep)

FEINTRO3

1,650

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3900 4100 4300 4500 4700 4900 5100

Body Mass (g)

Peak

Fre

qu

en

cy (

kHz)

FEI

NTR

O3

y = -1.661x + 2.535; r2 = 0.470; P < 0.0001

Dominant frequencies of yodels are related to male body mass

Mager, et al. 2007

Pairs respond differently to yodels of lower frequency

Friedman’s χ2 = 10.20 ; N = 42; P = 0.0061 Friedman’s χ2 = 12.78 N = 42; P = 0.0017

Mager, et al. 2007

Not Land

Land

Res

po

nse

Non-resident FEINTRO3 Peak Frequency (kHz)

Intruders land to high-frequency non-resident yodels?

Logistic Likelihood Ratio χ2 = 5.985; N =33; P = 0.0144

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Peak Frequency (kHz) FEINTRO3

# R

epe

at S

ylla

ble

s /

Yod

el

y = -8.489x – 11.520; r2 = 0.142; P = 0.0077

High-frequency yodelers give more repeat phrases per yodel

Yodel Acoustic Structure: Aggressive “Motivation”

(Barklow 1979, Mager et al. 2012, in prep)

# REPEAT PHRASES

Variability in # repeat phrases: Longer yodels = heightened aggressive state

Males give more repeat phrases when risk of attack is greater

Repeated-measures ANOVA F4,216 = 6.207; P < 0.0001; N = 44 males

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Flyover Distant Intruder Close Intruder Social Gathering Chase/Fight

Nu

mb

er

of R

ep

ea

t P

hra

se

s/Y

od

el

Mager, et al. 2012

Did the duration of yodels change after

adding platforms?

3

3.25

3.5

3.75M

ean

Nu

mb

er o

f R

epea

t P

hra

ses

2002 2003

Year

*

* Repeated-measures ANOVA F1,18 = 4.491, P = 0.048

Mager et al. 2010

Information communicated by yodel:

Dominant frequencies communicate body mass/condition

# repeat syllables communicate aggressive “motivation”

Do males of poorer condition compensate by being more “motivated”?

What factors ensure signal reliability, or “honesty”?

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Yodel Acoustic Structure: Individual Identity (Walcott et al. 1999, 2006; Lindsay 2000)

FINTRO3

DGA

P DINTRO

FINTRO1U F2RPT1B F1RPT1A

D1RPT1B

DGAP2

Why would individual recognition be important for divers?

Recognition of territorial threats: •Male recognition of territorial rivals (Mager et al. 2010)

•Female recognition of mates (Mager & Walcott, in press)

Recognition of kin: •Chick recognition of fathers from threats •Male/female future recognition of sons, fathers, grandfathers, grandsons, etc.

Resident Males respond more

aggressively to non-neighbor yodels

0

0,2

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0,6

0,8

1

1,2

1,4

1,6

Neighbor Non-neighbor

# Y

od

els

/ 1

0 m

in a

fter

Pla

yback

*

*Wilcoxon Z = 2.6, N = 20, P = 0.01 (Mager, et al. 2010)

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Diver communication “networks”

Great Northern Divers change their

yodels when they change territories (Walcott et al. 2006)

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Network consists of eavesdroppers

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Wayne Albertson

0,8

0,9

1

1,1

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0,8 1 1,2 1,4

Son D

ura

tion (

sec)

Father Duration (sec)

Possible relationship between duration

components of repeat phrases

Slope = 0.312, df = 19, P = 0.025

Granddad

Dad

Son/Grandson

Value of learning more:

Diver Conservation & Management:

Acoustic signals are important to habitat selection & defense

Acoustic signals reflect individual condition & resource value

Vocal Signaling within a Non-Oscine Bird:

Acoustic signals within acoustic “networks” & “neighborhoods”

Acoustic signals within a long-lived species with natal fidelity

http://www.iyufera.com/data/photos/920_1pacific_loon_call_2.jpg

THANK YOU!!!!

Dr. Andre Dhondt, Dr. H. Kern Reeve, and Dr. Sandra Vehrencamp, Cornell

University, Dr. Walter Piper, Dr. David Evers, Dr. Mark Pokras, Dr. Amy

McMillan, Dr. James Paruk, Dr. Alec Lindsay, Dr. Judith McIntyre

Numerous Field Assistants: N. Banfield, M. Gibbon, R. Hart, B. Lampe, D.

Reid, M. Schwabenlander, A. Webber, A. & J. Reiman, F. Spilker, E.

Harrington, C. Ritchie, V. Abernathy, D. Salsbury, J. Backus, E. Nebgen, D.

Woods, K. Trinkle, K. Klotz

Supporting Agencies: M. Meyer & R. Eckstein, WDNR, Loon Preservation

Committee

Financial Support: Cornell Lab of O. W. E. Benning Fellowship, Kieckhefer

Adirondack Fellowship, M. B. Sussman Fellowship, Sigurd T. Olson Loon

Research Award, Sigma Xi Grants in Aid of Research, National Science

Foundation, Cornell University Dept. of Neurobiolgy and Behavior Research

Award, Ohio Northern University Faculty Research Grant

? ? ?

Pe

ak

Fre

qu

en

cy

Sylla

ble

2 R

pt

Ph

ras

e 2

(k

Hz)

Individuals

Sons produce higher frequency yodels

*

Paired t = 2.388, df = 19, P = 0.0137

Yo

del D

ura

tio

n (

seco

nd

s)

Group

Sons tend to produce longer yodels

*

Paired t = 1.901, df = 19, P = 0.0367

What is Communication?

Sender Receiver Information

Decision & Response

MESSAGE

MEANING

Smith, W.J. (1965)

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gre

ssiv

e E

nco

un

ters

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cial

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pro

ach

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usi

on

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Did contests escalate on treatment territories?

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# C

hic

ks

Hat

ched

/ E

gg

Lai

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# C

hic

ks

Fle

dged

/ E

gg L

aid

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Platform territories experienced lower

reproductive success during the treatment year.

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*signficant at an of 0.05 (Mann-Whitney Z test)

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Pairs tremolo more to yodels having more repeat phrases

Linear Growth Model F1,112 = 5.26; P = 0.023

Mager, et al. 2012

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