Ageing and sexing of Asian chats - British Birds...484 British Birds102 • September 2009 •...

482 © British Birds 102 • September 2009 • 482–493

Of all the vagrant passerines reachingwestern Europe from eastern Asia, feware more highly sought-after than the

smaller chats. Three highly charismatic speciesof the genus Luscinia are long-distancemigrants, breeding in Siberia west to at least theOb River and wintering in southeast Asia:Siberian Rubythroat L. calliope, Siberian BlueRobin L. cyane and Rufous-tailed Robin L.sibilans. In western Europe, all are extremely rarebut highly prized autumn vagrants, and their

occasional appearances raise hopes that thesemay be repeated in future years. Anotherpredominantly Siberian species, Red-flankedBluetail Tarsiger cyanurus, has expanded itsbreeding range from Russia into easternFinland, where a small but increasing pop-ulation is estimated to be in the range of 50–500pairs (BirdLife International 2004), and a hand-ful also breed in Estonia (www.birdlife.org).Red-flanked Bluetails also winter in southeastAsia, but vagrants are being recorded with

Ageing and sexing of Asian chats:

Siberian Rubythroat, Siberian BlueRobin, Rufous-tailed Robin and

Red-flanked BluetailPaul J. Leader

ABSTRACT Three species of small chat that breed in western Siberia haveoccurred as vagrants to western Europe: Siberian Rubythroat Luscinia calliope,

Siberian Blue Robin L. cyane and Rufous-tailed Robin L. sibilans. A fourthspecies, Red-flanked Bluetail Tarsiger cyanurus, breeds across Siberia west

to eastern Finland and now occurs annually in western Europe.This paperprovides detailed ageing and sexing criteria for these species; it concentrates

on autumn plumages, as these are the most likely to be encountered inwestern Europe.

Red-flanked Bluetail Tarsiger cyanurus Alan Harris

increasing frequency in western Europe,particularly in autumn, and there were no fewerthan eight British records in 2007 and 12 in 2008(Hudson et al. 2008, in press).

Moult strategy and ageing criteriaEstablishing the age and sex of these species inautumn, particularly in a vagrant context, hasnot been well described in the literature. Thispaper discusses and illustrates ageing andsexing criteria for each species in the hand, and,with care, many of the features described canalso be applied in the field. Emphasis is placedon autumn plumages, which are the most likelyto be encountered in west-ern Europe. The criteriadescribed are based uponexperience gained in easternAsia, primarily in HongKong, where all four speciesoccur as regular passage mig-rants and/or winter visitors.

Juvenile plumage in allfour species is characterisedby its drab and brownappearance, with extensivepale body spotting, and paletips to the coverts andtertials. With the exceptionof Red-flanked Bluetail ineastern Finland, none of thespecies discussed here islikely to be encountered inEurope in juvenile plumage,as this is replaced during thepost-juvenile body moult tofirst-winter plumage on orclose to the breedinggrounds before the start ofautumn migration.

MoultAfter fledging, young birdsundergo a partial post-juven-ile moult during which thebody plumage is replaced,usually together with thelesser, median and a variablenumber of the greatercoverts (beginning with theinnermost and continuingtowards the outer edge ofthe wing). Birds in first-

winter plumage thus retain the juvenile tail, pri-maries, secondaries and tertials, together withany unmoulted juvenile greater coverts. Adultsundergo a complete post-breeding moult, afterwhich the entire plumage is of the same age.

AgeingFirst-winter birds in autumn almost alwaysshow a moult contrast in the greater coverts(between uniform, adult-type inner greatercoverts and retained juvenile outer greatercoverts, which are characterised by a pale spot atthe tip); establishing the age is straightforwardin the hand, but relies on good views in the field.

Ageing and sexing of Asian chats

483British Birds 102 • September 2009 • 482–493

290. Juvenile Siberian Rubythroat Luscinia calliope, Amurskaya Oblast, RussianFederation, 12th July 2007. A typical juvenile chat with extensive spottingabove and below; the juveniles of all four species discussed in this paper

have similar body feathering, which is replaced prior to the autumn migration.Pa

ul J.

Lead

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291. Adult male Siberian Rubythroat Luscinia calliope, Hong Kong*, China,25th February 2003. Note the distinctive grey wash below the red throat

patch, which is characteristic of adult and some first-winter males.

Paul

J.Le

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* Note: ‘Hong Kong’ refers to the Hong Kong Special Administrative Region, People’s Republic of China.

484 British Birds 102 • September 2009 • 482–493


Correspondingly, adults lackmoult contrast in the greatercoverts. As with other smallchats, there are also subtlebut characteristic differencesin tail-feather shape betweenadults and first-winters:adults have broader andmore rounded tips to the tailfeathers, whereas juvenileshave narrower and morepointed tips.

Siberian Rubythroat Ever since the first Britishrecord of Siberian Ruby-throat, on Fair Isle inOctober 1975 (Lowe 1979),there has been a lack ofclarity in the Europeanliterature regarding theageing and sexing of thisspecies. The presence oftraces of red on the throat ofthe Fair Isle bird led thefinders to think that it wasprobably a first-winter male(Lowe 1979), while discus-sion relating to the age andsex of more recent Britishrecords (e.g. Hunt 1997,Osborn 2001) has furtherhighlighted the problems oflimited information. InHong Kong, where SiberianRubythroat is a commonwinter visitor and passagemigrant (Carey et al. 2001),it shows a relatively highdegree of site fidelity, withmany birds establishing andreturning to the same winterterritories. Consequently,year-on-year retraps (i.e.known adults) are quitecommon, and this hashelped to establish thevalidity of the featuresdiscussed below.

Sex-related differencesIn general, males have abright red throat in allplumages other than

294. First-winter male Siberian Rubythroat Luscinia calliope, Hong Kong,China, 14th February 2004.This well-marked first-winter male would beinseparable from an adult on the features visible here, and ageing would

depend on the pattern of the greater coverts and tertials (see text).

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J.Le

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293. First-winter male Siberian Rubythroat Luscinia calliope, Hong Kong,China, 1st November 2003.This poorly marked first-winter male shows

reduced black feathering around the eye that, together with whitish tips to the red throat feathers, results in a drabber and less contrasting appearance to the head compared with the adult in plate 291. Note also the browner

wash to the upper breast, which is typical of first-winter males.

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J.Le

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292. Adult male Siberian Rubythroat Luscinia calliope, Hong Kong, China,2nd December 2003.There is some variability in the appearance of males,which is not age-related. On this adult, the red throat patch is less intense,and the black on the lores and surrounding the eye is less extensive than on the bird in plate 291. There is a slight pinkish wash to the supercilium

and submoustachial.

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juvenile. Females are usuallyduller and frequently lackred on the throat altogether.Some show a limited amountof red on the throat, butmore typically they havepink or off-white throats.However, some adult femalesappear remarkably similar tomales.

Adult and first-winter malesIn adult and first-wintermale plumages, SiberianRubythroat has a stunningcombination of iridescentruby-red throat, black loresand a well-defined whitesubmoustachial stripe. Atthe base of the red throatpatch there is often a narrowblack border, below whichthe upper breast is distinctlygrey. On poorly markedbirds, however, the darkborder is absent and theupper breast is brown ratherthan grey. Such poorlymarked birds are usually,though not always, first-winter males. In freshautumn plumage, a fewfirst-winter males may shownarrow dark tips to thefeathers.

There is slight individualvariation to this headpattern, with some birdsexhibiting a faint pink washto the supercilium and sub-moustachial, and othersshowing more extensiveblack lores. This variation isnot age-related.

Adult femaleAlthough some adult femaleslack any trace of pink or redon the throat, most have ahead pattern that is awashed-out version of themale’s. However, a smallminority, perhaps olderfemales, show a head pattern

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296. Adult female Siberian Rubythroat Luscinia calliope, Hong Kong,China, 14th January 2006. Some adult females lack any trace of pink

or red on the throat and in this respect resemble first-winter females.

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297. Adult female Siberian Rubythroat Luscinia calliope,Amurskaya Oblast,Russian Federation, 12th July 2007.The sex of this strongly marked adult

female, trapped on the breeding grounds, was confirmed using shape of thecloacal protuberance and extent of the brood patch (cf. Svensson 1992).

Note the entirely black bill, which is typical of both sexes in breeding condition.

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J.Le

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295. Adult female Siberian Rubythroat Luscinia calliope, Hong Kong,China, 18th December 2004.This is a typical adult female: the throat has

a pink wash and the head pattern is a subdued version of the male’s.Note also the narrow band of white at the base of the pink throat patch.



298. First-winter female Siberian Rubythroat Luscinia calliope, Hong Kong,China, 6th November 2005. A typical first-winter female, lacking all

traces of red on the throat.This bird cannot be reliably aged on features visible here, and ageing relies on the pattern to the tips

of the greater coverts and tertials.

Paul

J.Le

ader

that is strikingly similar tothat of a male. Typically,most adult females show anoff-white supercilium whichis usually poorly defined atthe rear, dark brown or blacklores (contra Svensson 1992),a diffuse, off-white sub-moustachial, and a pale pinkto reddish-pink throat. Adistinctive feature of themajority of adult females is awhite band of variable widthbelow the throat patch; afeature not shown by malesof any age.

Females that closelyresemble males (c. 5% of alladult females) can be sepa-rated from them by the morediffuse submoustachial (oftenwith slightly darker feathertips, creating a faint mottledeffect), narrower superciliumand lack of a dark border tothe lower throat. In addition,only exceptionally would awell-marked female showpure grey below the redthroat patch and then only asa very narrow border. Suchwell-marked females can beextremely difficult to separatefrom males, although smallerindividuals with a winglength below 76 mm can beseparated in the hand (seetable 1).

First-winter femaleFirst-winter females have apoorly marked head pattern,and only exceptionally showeven a trace of pink on thethroat. Only one bird,trapped in spring, out ofabout 50 first-winter femalesexamined, showed any hintof pink on the throat. Thesupercilium is buff, rarelyoff-white, the submous-tachial is also off-white tobuff, although on some birdsthis is reduced to a pale spot

300. Adult male Siberian Rubythroat Luscinia calliope, Hong Kong, China,14th February 2000. Same bird as in plate 291.Aged as an adult by the uniform greater coverts and tertials. Note also the narrow pale tips

to the tail feathers, a feature of adults.

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J.Le

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299. First-winter female Siberian Rubythroat Luscinia calliope, Hong Kong,China, 2nd December 2003. On a minority of first-winter females, such

as this individual, the supercilium is poorly developed, the lores and throat are brown and the spot at the base of the lower mandible is obscured

with brownish feather tips.

Paul

J.Le

ader



at the base of the lowermandible. The throat is off-white and contrasts with thegrey-brown upper breast,although the border betweenthe two is diffuse and poorlydefined. Some are even lesswell marked, showing anindistinct supercilium thatbarely extends to the eye,only faintly darker lores, atiny pale spot at the base ofthe bill, and a throat which,except for some paler feath-ering at the base of the lowermandible, is grey-brown andconcolorous with the breastand flanks. Such birds oftenhave pronounced specklingor scaling on the underpartswhich, combined with thepoorly marked head pattern,does not fit the generallyperceived appearance ofSiberian Rubythroat.

Age-related differencesFirst-winters typically moultvery few greater coverts, andretained juvenile feathersgenerally show conspicuouspale spots or tips. These varyfrom tiny pale spots (c. 1 mmacross) to broad buff tips;birds with such broad paletips often show obvious paletips to the primary covertstoo. These pale tips aresubject to wear over thecourse of the winter and byspring may be almostcompletely abraded on somebirds. Others, however,retain pale tips well into thebreeding season. Adult-typetertials and greater covertslack the pale tips andcharacteristically have anarrow, well-defined olive-brown fringe.

First-winters that havemoulted some greatercoverts show a distinctmoult contrast between

301. First-winter male Siberian Rubythroat Luscinia calliope, Hong Kong,China, 26th November 2005. Readily aged as a first-winter by the pale

tips to the greater coverts, and the pale tip to the shortest tertial.

Paul

J.Le

ader

302. Adult female Siberian Rubythroat Luscinia calliope, Hong Kong,China, 2nd December 2004. A typical adult female, showing a pinkish wash

to the throat and aged by the lack of pale tips to the greater coverts.

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J.Le

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303. First-winter female Siberian Rubythroat Luscinia calliope, Hong Kong,China, 2nd December 2003 (same bird as in plate 299). Pale tips to the greater coverts readily age this as a first-winter. It is slightly browner than typical adult and first-winter females, and shows faint speckling

or scaling to the underparts.

Paul

J.Le

ader

uniform, adult-type inner greater coverts andretained juvenile outer greater coverts. Very fewfirst-winters appear to moult all the greatercoverts and tertials. I have not encountered thisamong c. 250 first-winters handled; althoughpossible, it must be extremely rare.

A less obvious ageing criterion is the pres-ence or absence of pale tips to the outer tailfeathers. Adults show narrow pale tips to the tailfeathers, while first-winters typically do not;exceptionally, they may show a faint trace ofpale fringing. In the hand, the shape of the tailfeathers is a useful character for ageing (seeabove).

The presence of a pale base to the bill is notage-related (contra Hunt 1997) as, outside thebreeding season, all Siberian Rubythroats showthis. When in breeding condition, both sexestypically have an entirely black bill.

BiometricsAlthough there is some overlap, males averagelarger than females, and adults average slightlylarger than first-winters (table 1). Note that allwing measurements given in this paper use themaximum-wing-chord method (Svensson 1992).



Table 1. Wing length (mm) of Siberian RubythroatsLuscinia calliope trapped in Hong Kong, 1987–2005.

Siberian Rubythroat Max. Min. Mean n

Adult male 86 76 81.9 72

Adult female 81 71 77.2 38

First-winter male 86 75 80.5 261

First-winter female 81 71 76.6 88

304. Adult male Siberian Blue Robin Luscinia cyane,Hong Kong, China, 4th April 1992.The blue outer

webs to the primaries establish this as an adult rather than a first-summer male.

Pete

r R.

Kenn

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y

Siberian Blue Robin This is a fairly straightforward species to age andsex, although there is considerable variation infirst-winter male plumage. First-winter femalesoften lack any hint of blue in the plumage, evenin the tail, and may present an unexpectedlydifficult identification challenge given theskulking nature of this species.

Age- and sex-relateddifferencesAdult maleAdult males are unmistak-able, being entirely blueabove, including the wing-coverts, tertials, and outeredges to the primaries andsecondaries. The underpartsare white, with a blackborder separating the blueupperparts from the whitethroat and breast.

Adult femaleAdult females are ratherdrab, with grey-brownmantle and scapulars,although some show a hint

305. Adult female Siberian Blue Robin Luscinia cyane, Honshu, Japan, 7th June,2009. Adults are aged by the uniform greater coverts and tertials, which lackpale or rufous tips. Some adult females show a hint of blue on the nape and

mantle, like this bird, although most lack this and appear rather drab grey-brown.

Paul

J.Le

ader

of blue on the nape andmantle. This is never aspronounced as that onthe rump, uppertail-coverts and tail, whichvary in colour frombright blue (similar tothat of an adult male) toa much duller blue-grey.The greater coverts andtertials are all of thesame age and appearuniform brown, lackingany pale or rufous tips.

First-winter maleThe extent of the post-juvenile moult is quitevariable in males. None-theless, all show at leastsome bright blue on therump, uppertail-coverts,tail, lesser and median coverts, and scapulars.Some birds retain all of their juvenile greatercoverts but more advanced birds show obviouscontrast between replaced inner and rufous-brown juvenile outer greater coverts, as well asunmoulted, brown-edged primaries andsecondaries, and appear blue above. Such birdsstill show a buff wash to the throat and breast,and some scalloping to the throat and upperbreast, until the pre-breeding body moult inspring.

First-summer maleFollowing the pre-breeding body moult, first-summer males resemble adult males, but theretained juvenile primaries and secondaries arebrown-edged and contrast with the blueupperparts and wing coverts.

First-winter femaleFirst-winter females usually lack all traces ofblue in the plumage. Like first-winter males,they may show moult contrast in the greatercoverts, juvenile feathers having a distinct buffor rufous fringe. They differ from first-wintermales by their uniform dark brown upperparts,including the rump, uppertail-coverts and tail.Such birds are also often quite dark on the throatand breast but still show darker scalloping onthe upper breast.



306. First-winter male Siberian Blue Robin Luscinia cyane, Hong Kong, China,22nd September 2005. First-winter males lack the distinctive appearance of adultand first-summer males, and instead show a buff wash and some scalloping to thethroat and breast, which are retained until the pre-breeding body moult in spring.

Moult contrast in the greater coverts, with two retained juvenile feathers,provides further evidence of its age.

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307. First-winter male Siberian Blue Robin Lusciniacyane, Hong Kong, China, 10th September 2003.

The extent of blue in the upperparts variesindividually. All first-winter males show at least

some bright blue on the rump, uppertail-coverts,tail, lesser and median coverts, and scapulars, but

compared with the bird in plate 306, this individualshows much less blue on the mantle, scapulars and

wing coverts.The extent of post-juvenile moultvaries individually too; this bird has replaced

only two inner greater coverts.

Paul

J.Le

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Rufous-tailed Robin This species appears to lackany sex-related differences inappearance, and there is verylittle variation between first-winter and adult plumages.Some older references (e.g. LaTouche 1925–30) suggestedthat males have brighter tailsthan females, and while thismay explain the variation intail colour in this species, thishas yet to be confirmed.

Age-related differences Adult male and femaleThe lack of moult contrast inthe greater coverts (whichappear uniform brown, as dothe tertials) and the tail-feather shape are the maincriteria for ageing.

First-winterFirst-winters usually retain atleast some juvenile greatercoverts until the first completemoult, when they are approxi-mately 12 months old. Juvenilegreater coverts are brown witha rich buff tip and, frequently,a rufous fringe along the outerweb of each covert. First-winters may also show tinypale tips to the lesser/mediancoverts and/or the tertials. Anymoulted adult-type greatercoverts will show contrastwith retained (pale-tipped)juvenile coverts.

Red-flanked BluetailWith the exception of adultmales, Red-flanked Bluetailscan be difficult to age and sexaccurately, particularly inautumn. Many are simplyreferred to as ‘female or first-winter’, even in regions wherethey occur commonly, whichpartly reflects the limitednature of the literature butalso the subtleties of some ofthe characters and the diffi-

308. First-winter female Siberian Blue Robin Luscinia cyane, Hong Kong,China, 7th September 2002. First-winter females usually show uniform darkbrown upperparts, including the rump, uppertail-coverts and tail, and lack

all traces of blue in the plumage. Like first-winter males, they usually show moult contrast in the greater coverts.

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J.Le

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Pa

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310. First-winter Rufous-tailed Robin Luscinia sibilans, Hong Kong,China, 11th November 2002.This individual has retained most of its pale-tipped, juvenile greater coverts, which contrast with the plain adult-typefeathers.These pale tips often extend as a rufous fringe along the outer

web of each greater covert.

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J.Le

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309. Adult Rufous-tailed Robin Luscinia sibilans, Hong Kong, China, 4thNovember 2007.Tail shape and lack of moult contrast in the greater covertsprovide the best means of separating adults and first-winters. Males and femalesof all ages cannot be separated on plumage and biometrics, even in the hand.

culties of seeing the mostuseful features well.

Unlike Siberian Ruby-throat, Red-flanked Bluetail isnot faithful to particular win-tering sites in Hong Kong andmuch of the detail providedbelow is based upon theapplication of ‘first principles’towards ageing and sexing.However, all the features men-tioned here were discussedwith Yoshimistu Shigeta, whois familiar with Red-flankedBluetails on the breedinggrounds, having handledseveral hundred recapturedbirds of known age. Conse-quently, the criteria outlinedbelow are believed to be validand robust.

Age- and sex-relateddifferencesAdult maleAdult males are unmistakable,with bright blue upperpartsand tail, a narrow white throatand orange flanks. One partic-ularly variable feature of adultmales is the colour of the pri-maries and secondaries, espe-cially the outer webs. Manyshow a mixture of brown andblue outer webs to the pri-maries, and very few birdsshow either entirely blue orentirely brown primaries.Breeding birds in Japan showonly individual, not age-related variation (Y.Shigeta in litt.), and all adult males trapped inHong Kong have shown extensive individual vari-ation in this feature (but not in other age-relatedfeatures). Cramp et al. (1988) suggested that adultmales occur in two colour morphs (blue – thetypical male, and brown – which resembles theadult female) but there is no evidence for this,and it may relate to confusion with first-yearmales that breed in a female-like plumage.

Adult femaleAdult females are typically brown above withcontrasting blue rump, uppertail-coverts andtail, and they are difficult to separate from first-



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312. Adult female Red-flanked Bluetail Tarsiger cyanurus, Hong Kong,China, 12th December 2000.Adult females are particularly difficult to

separate from first-winters of either sex. Differences in tail-feather shapeprovide the most reliable means of ageing. Supporting features include auniform outer web to the greater coverts that contrasts with a darker

inner web, and unmarked tertials.

311. Adult male Red-flanked Bluetail Tarsiger cyanurus, Hong Kong,China, 12th December 2000. Adult males are unmistakable, with bright

blue upperparts and tail, a narrow white throat and orange flanks.There isvariability in colour and extent of blue on the outer webs of the primaries:

many show a mixture of brown and blue outer webs to the primaries,and very few show either entirely blue or entirely brown primaries.

winters of either sex. They typically show auniform outer web to the greater coverts (whichcontrasts with the darker inner web whenvisible) and plain tertials (see below for first-winters). Very occasionally, they also show blueon the lesser coverts and/or scapulars.

In the hand, adult females are readilyseparable from first-winters by the shape of thetail-feather tips: broad and rounded on adultsand narrow and more pointed on first-winters.

First-winter maleTail-feather shape (see above) is the single mostreliable criterion for separating first-wintersfrom adults. First-winter males otherwise



closely resemble adultfemales, but show either asmall pale spot at the tip ofeach greater covert or, morecommonly, a pale buff fringe.In the latter case, the bufffringes form a subtle wing-bar, but this may be extremelydiffuse and many birds arenot easily aged using thisfeature. The tertials are alsousually pale-fringed, and aresubtly more pointed thanthose of adults.

A small proportion offirst-winter males show blueon the lesser coverts and/orscapulars; rarely, some adultfemales also show this. Conse-quently, lesser-covert and/orscapular colour cannot berelied upon in isolation to agebirds showing this feature asfirst-winter males.

First-winter femaleAgain, tail-feather shape is themost reliable feature to distin-guish adults from first-winters. Separation of first-winter males and females isextremely difficult and insome cases impossible. First-winter females tend to haveslightly paler, greyer tailfeathers than males and,although there is someoverlap, first-winters with palegrey-blue tails (see plate 319)can be safely sexed as females.Furthermore, first-winterfemales do not show blue onthe lesser coverts or scapulars.The majority of first-winterscannot be sexed, even in thehand (table 2).

BiometricsAlthough there is someoverlap, adult males tend to beslightly larger than adultfemales (table 2). It can also beseen that the wing length offirst-winter males is consider-

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315. First-winter Red-flanked Bluetail Tarsiger cyanurus, Hong Kong,China, 23rd December 2000.This first-winter shows extremely

pronounced pale tips to the greater coverts.

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314. First-winter Red-flanked Bluetail Tarsiger cyanurus, Hong Kong, China,20th November 1999.This first-winter, thought to be a female, has poorly

marked pale tips to the greater coverts but was aged using tail-feather shape.

313. First-winter male Red-flanked Bluetail Tarsiger cyanurus, Hong Kong,China, 23rd December 2000.This bird closely resembles the adult female inplate 312, but can be aged by the slightly narrower and more pointed tips to

the tail feathers, while the pale-fringed tertials are perhaps slightly morepointed, and a diffuse, pale buff fringe forms a very subtle

wing-bar along the tips of the outer greater coverts.

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ably shorter than that of adult males andoverlaps with that of all unsexed birds,confirming that first-winter birds cannot besafely sexed using wing length.

Acknowledgments

I would like to thank Yoshimistu Shigeta of the YamashinaInstitute for Ornithology, Japan, for his assistance andcomments on aspects of ageing chats during the breedingseason.

References

BirdLife International. 2004. Birds in Europe: population



Table 2. Wing length (mm) of Red-flankedBluetails Tarsiger cyanurus trapped in Hong Kong,

1989–2005.

Red-flanked Bluetail Max. Min. Mean n

Adult male 85 77 80.6 82

Adult female 83 71 77.8 157

First-winter male 82 72 78.4 100

First-winter (unsexed) 82 73 77.2 295

Paul J. Leader, c/o Asia Ecological Consultants, 127 Commercial Centre, Palm Springs,New Territories, Hong Kong

316. Adult male Red-flanked Bluetail Tarsiger cyanurus,Hong Kong, China, 20th December 2000.

Note the broad, rounded shape to the feather tips, which is particularly obvious on the central

pair of tail feathers.

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Paul

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319. First-winter female Red-flanked Bluetail Tarsigercyanurus, Hong Kong, China, 23rd December 1999.The tail of this first-winter female shows a slight

greyish cast to the blue feathering, which males lack.Tail shape as for first-winter male (see plate 318).

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318. First-winter male Red-flanked Bluetail Tarsigercyanurus, Hong Kong, China, 14th November 1999.

Compared to those of the adults in plates 316 and 317,the individual rectrices of this first-winter have narrower

and more pointed tips, particularly the central pair.

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317. Adult female Red-flanked Bluetail Tarsigercyanurus, Hong Kong, China, 20th December 2000.

The tail feathers of Red-flanked Bluetail are generallymore pointed than those of Luscinia chats. Although the tail feathers of this adult appear quite pointed,

the central pair are wider at the tip, and slightly more rounded, than those of a first-winter.

estimates, trends and conservation status. BirdLifeConservation Series 12. BirdLife International,Cambridge.

Carey, G. J., Chalmers, M. L., Diskin, D.A., Kennerley, P. R.,Leader, P. J., Leven, M. R., Lewthwaite, R.W., & Young, L.2001. The Avifauna of Hong Kong. Hong KongBirdwatching Society, Hong Kong.

Cramp, S. (ed.) 1988. Handbook of the Birds of Europe theMiddle East and North Africa.Vol. 5. OUP, Oxford.

Hudson, N., & the Rarities Committee. 2008. Report onrare birds in Great Britain in 2007. Brit. Birds 101:557–558.

— & —. In press. Report on rare birds in Great Britain in 2008. Brit. Birds 102.

Hunt, I. 1997. Siberian Rubythroat in Dorset. Birding World10: 390–391.

La Touche, J. D. D. 1925–30. A Handbook of the Birds ofEastern China.Vol. 1.Taylor & Francis, London.

Lewington, I., Alström, P., & Colston, P. 1991. A Field Guide to the Rare Birds of Britain and Europe. Collins, London.

Lowe,A. R. 1979. Siberian Rubythroat: new to Britain andIreland. Brit. Birds 72: 89–94.

Osborn, K. 2001.The Siberian Rubythroat on Shetland.Birding World 14: 426–427.

Svensson, L. 1992. Identification Guide to EuropeanPasserines. 4th edn. Privately published, Stockholm.

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