Alan Harris Siberian Flycatcher sibirica Brown, Siberian and Grey-streaked Flycatchers: identification and ageing Paul J. Leader

Abstract In the light of recent records of Brown Flycatcher Muscicapa dauurica in Britain, this short paper looks at the identification and ageing of this and two closely related potential vagrants from east Asia: Siberian Flycatcher M. sibirica and Grey-streaked Flycatcher M. griseisticta. Differences in structure and are summarised, and particular attention is paid to ageing and moult.

rown Flycatcher Muscicapa dauurica, Europe on several occasions, including single Siberian Flycatcher M. sibirica, and records from Denmark, Sweden and Greece BGrey-streaked Flycatcher M. griseisticta plus three accepted records from Britain (Fair are three superficially similar flycatchers which Isle 1992 and 2008 and Flamborough Head, are common, long-distance migrants in east Yorkshire, 2007; Hudson et al. 2009, Harvey Asia. Brown Flycatcher has already reached 2010). In addition, one was seen in Yorkshire

Throughout this paper only the northern taxa of Siberian Muscicapa s. sibirica and Brown Flycatchers M. d. dauurica are discussed. Although there exists another ‘Brown Flycatcher’ in Asia (Sumba Brown Flycatcher M. segregata), the English name of Brown Flycatcher for M. dauurica has a long history in Europe and there seems little need to add the modifier ‘Asian’ to avoid potential confusion with Sumba Brown Flycatcher. For M. s. sibirica, I prefer the English name Siberian Fly- catcher over Dark-sided or (both of which are widely used in Asia) to distinguish the northern migratory populations from three very similar Sino-Himalayan taxa (which are morphologically distinct from nominate sibirica, being smaller, much darker and showing more heavily marked underparts, and are either resident or short-distance migrants; Vaurie 1959). This group (the Sino-Himalayan taxa or ‘cacabata group’) is sometimes treated as a distinct species, Dark-sided Flycatcher M. cacabata. In this context, it is of note that plates 294–295 in Bradshaw et al. (1991) showing a ‘Siberian Flycatcher’ were taken in Sichuan Province, China, in May (G. Speight pers. comm.). As a consequence, they depict the taxon rothschildi (i.e. part of the ‘cacabata group’; Vaurie 1959), which breeds in this region of China and is not representative of nominate sibirica. The latter is the only taxon likely to reach Europe as a vagrant.

658 © British 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers Martin Hale 360. First-winter Brown Flycatcher Muscicapa dauurica, Hong Kong, China, 6th September 2006. Note especially the pale, cold grey upperparts of this compared with Siberian M. sibirica and Grey-streaked Flycatchers M. griseisticta.The broad pale fringes to the tertials and greater coverts, and especially the pale ‘hooks’ extending up the feather shaft at the tips of the latter are typical of first- winter Brown Flycatchers. Note also the primary projection, which is slightly shorter than the length of the exposed tertials, and the relatively long tail. The extensively pale lores of this individual results in the eye-ring being difficult to discern in front of the eye but very conspicuous behind it. This view shows the typically large bill of this species as well as the predominantly pale lower mandible. in early September 2010. Although neither species were measured. These specimens Siberian nor Grey-streaked Flycatchers have comprised a mixture of adults and first-years yet occurred in western Europe, other and were restricted to individuals of migrants that occupy a similar northern migratory populations. breeding range have reached Europe, which suggests that both flycatchers are potential Ageing vagrants. Furthermore, there is a remarkable Brown Flycatcher record of a vagrant Siberian Flycatcher from In autumn, first-winters can be separated Bermuda (Wingate 1983). readily from adults by the presence of neat, While the identification of ‘brown fly- pale edges to the greater coverts and tertials, catchers’ has been addressed in the past, most while the tips of these feathers have a broader notably by Bradshaw et al. (1991) and pale area with a characteristic ‘hook’ (or Alström & Hirschfeld (1991), it seems timely ‘thorn’) extending back along the feather to revisit this topic in the light of the recent shaft. These differ from the narrower, greyer British records of Brown Flycatcher and also fringes to the tertials and greater coverts improvements in bird photography. In this shown by adults, and which lack the obvious paper, emphasis is placed on ageing these hook pattern. It should be noted that on species in the field, especially where this has some adults the tertial fringes are paler than implications with regard to species identifica- the greater-covert fringes. See plates 360–364. tion. In addition to studying all three species In broad terms, similar distinctions between in the field, museum specimens have been adult and first-winter birds are apparent in examined and, for the biometrics presented the other two species, though there are here, a sample of 20 specimens of each important differences too, described below.

British Birds 103 • November 2010 • 658–671 659 Leader

Brown Flycatcher Siberian Flycatcher Grey-streaked Flycatcher 56

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tail length (mm) 48

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44 65 70 75 80 85 90 wing length (mm) Fig. 1. Wing length (mm) and tail length (mm) of Brown Muscicapa dauurica, Siberian M. sibirica and Grey-streaked Flycatchers M. griseisticta (n = 20 for each species). some, the greater coverts appear uniform and unmarked. This pattern is never shown by fresh adult Brown, although these tips can abrade during winter and may be lost by the spring. See plates 365–371.

Grey-streaked Flycatcher The greater coverts and ter- tials of first-winter Grey- streaked have a well-defined pale edge and (broader) tip but feathers in both tracts fre- quently lack any hook at the tip, resulting in a broad pale tip of even width. See plates 372–376.

Timing of post-juvenile moult

Alan Harris A useful character that helps Fig. 2. Diagram showing the relative proportions of wings and with species identification is tail of first-winter Brown Muscicapa dauurica (left), Siberian the timing of post-juvenile M. sibirica (middle) and Grey-streaked Flycatchers M. griseisticta moult. On average, this takes (right). Note the progressively longer primary projection and shorter extension of the tail beyond the wing-tip. place distinctly later in Siberian Flycatcher than in Siberian Flycatcher either Brown or Grey-streaked, both of which First-winter Siberian Flycatchers usually undergo a post-juvenile body moult before show a less obvious pale hook at the tip of they migrate. Siberian Flycatchers that retain the greater coverts than first-winter Brown, extensive juvenile plumage on the upperparts and often lack the pale hook at the tip of the and underparts are recorded regularly from tertials. Adults have less well-marked pale August to October, and occasionally into fringes than adult Brown Flycatchers and, on November. In comparison, during the same

660 British Birds 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers

Table 1. Comparison of wing length (mm), tail length (mm) and wing/tail ratio in Brown Muscicapa dauurica, Siberian M. sibirica, and Grey-streaked Flycatchers M. griseisticta. wing length tail length wing/tail ratio mean* range mean range range Brown Flycatcher 69.2 ± 1.7 66.5–72.0 47.9 ± 1.7 45.0–51.0 1.36–1.52 Siberian Flycatcher 79.7 ± 2.0 75.0–85.0 51.6 ± 2.0 47.0–55.0 1.48–1.62 Grey-streaked Flycatcher 85.8 ± 1.9 83.0–89.0 49.5 ± 1.9 46.0–53.0 1.66–1.84 * ± standard deviation. N = 20 for each species.

Table 2. Relative length of second primary (P2) compared with other primaries in Brown Muscicapa dauurica, Siberian M. sibirica, and Grey-streaked Flycatchers M. griseisticta. Figures represent percentage of individuals meeting each criterion, n = 20 for each species). P2=P3/4 P2=P4 P2=P4/5 P2=P5 P2=P5/6 Brown Flycatcher 00045 55 Siberian Flycatcher 0 10 90 00 Grey-streaked Flycatcher 25 65 10 00

gives a progressively longer primary projec- Table 3. Comparison of bill width (mm) tion and more pointed wing shape (table 2). measured at proximal edge of nostrils in Brown Muscicapa dauurica, Siberian These differences are clearly apparent in the M. sibirica, and Grey-streaked Flycatchers field. In Brown, the primary projection is M. griseisticta (n = 20 for each species). shorter than the exposed tertials, in Siberian it is equal to or up to 20% longer and in bill width Grey-streaked normally 20% longer than the mean range length of the exposed tertials. Brown Flycatcher 5.8 ± 0.2 5.3–6.1 In both Brown and Siberian, the primary Siberian Flycatcher 5.4 ± 0.3 4.8–5.8 tips typically fall level with or slightly short of Grey-streaked Flycatcher 5.4 ± 0.3 4.7–5.9 the tips of the longest uppertail-coverts, while in Grey-streaked the primary tips typi- period, first-winter Grey-streaked may show cally extend beyond the longest uppertail- just a small number of retained juvenile coverts. With flycatching birds, the distinctly feathers (if present, these are usually among long and pointed wings of Grey-streaked can the longest uppertail-coverts), while young be rather obvious, as can the more rounded Brown Flycatchers only exceptionally retain wing of Brown Flycatcher. Siberian Fly- juvenile feathers on the upperparts. catcher shows a rather pointed wing and is There is much individual variation in the more similar to Grey-streaked in this regard. timing of the post-juvenile moult in Siberian Flycatcher; in some, it is completed as early as Bill mid September, while in others it has barely When viewed from below, Brown Flycatcher commenced in mid November. Observations typically has a straight-sided or slightly in China in autumn (between August and convex bill, whereas both Siberian and Grey- early November) suggest that a bird retaining streaked show slightly concave or straight more than c. 25% juvenile body plumage is sides to the bill, and the bill generally appears invariably a Siberian Flycatcher. less bulky. Note, however, that the base of the bill can be similarly broad in all three species Structural differences (table 3) and that a small minority of Siberian Wing shape and primary projection and Grey-streaked have a bill shape identical There are distinct structural differences to that of some Brown Flycatchers. However, among the three species. Most important is when viewed from the side, the bill of an increase in wing length (and wing/tail Siberian is normally shorter and finer than ratio) from Brown through Siberian to Grey- that of both Brown and Grey-streaked, and streaked (table 1, figs. 1 & 2), which in turn both Siberian and Grey-streaked have a

British Birds 103 • November 2010 • 658–671 661 Leader smaller pale area at the base of the lower include ill-defined streaks). A few birds show mandible than Brown (such that on some a darker and more clearly defined breast- individuals of both species the lower band. Grey-streaked Flycatcher always shows mandible can appear all dark in the field). very dark, well-defined streaks on the breast and flanks; the contrast of these streaks being Plumage differences enhanced by the clean white ground colour Head pattern of the underparts. Brown Flycatcher has distinctly pale and Siberian Flycatcher is more variable below unmarked lores; a conspicuous, whitish eye- than either Brown or Grey-streaked. This can ring; a well-defined submoustachial and a cause confusion as the underparts of some neat lateral throat stripe; and a pale ‘half- may resemble those of a well-marked Brown collar’, giving it a subtle but quite distinctive Flycatcher, while others can appear more appearance. In comparison, Siberian Fly- similar to Grey-streaked. Young Siberian Fly- catcher typically shows less extensively pale catchers that retain largely juvenile plumage lores, a strong lateral throat stripe but less in autumn are distinctly spotted across the well-defined submoustachial, while the pale breast and onto the flanks, but those more half-collar is often ill-defined or absent. advanced into first-winter plumage show Together, these characters combine to create dark brown flanks and breast (this colour more of a uniformly hooded effect. Grey- generally extending farther down the flanks streaked Flycatcher shows less well-defined than in Brown). Adult Siberian Flycatchers pale lores than Brown but a more conspic- are rather similar to first-winters but gener- uous lateral throat stripe, and some streaking ally appear more streaked. Although the on the otherwise pale submoustachial. It can underpart streaking can be quite diffuse on sometimes have light streaking on the throat, some birds (and similar to a well-marked and also shows diffuse streaking on the Brown Flycatcher), in boldly marked birds crown, a feature not shown by either Brown the underparts are entirely streaked. When or Siberian. Owing to the more obviously compared with Grey-streaked, the streaks are and extensively pale lores of Brown Fly- much less distinct and may coalesce to form catcher, the part of the eye-ring in front of much longer streaks down the breast. the eye can be difficult to see in that species, Siberian may also show diffuse dark centres giving the impression of an incomplete eye- to the longest undertail-coverts, a character ring. The eye-ring on Grey-streaked Fly- which the other two species never show. catcher typically appears complete, owing to the contrast with the darker lores, but is often Wing-bars rather narrow and frequently slightly thicker First-winter Siberian Flycatchers tend to have behind the eye. Siberian usually shows a very more obvious rufous tones to the pale obvious eye-ring (partly a function of the greater-covert tips than either Brown or darker and plainer head of this species), Grey-streaked. which broadens conspicuously behind the eye. Underwing-coverts The underwing-coverts of both Siberian and Upperparts Grey-streaked are dark grey-brown, conspic- In fresh plumage, Brown Flycatcher has dis- uously darker than the rest of the underwing. tinctly greyer and colder upperparts than the The underwing-coverts of Brown Flycatcher darker brown upperparts of both Siberian are a paler mid brown, less obviously darker and Grey-streaked. than the rest of the underwing.

Underparts Retained juvenile feathers Brown Flycatcher is the least well marked of As well as the differences in timing of post- the three species on the underparts, showing juvenile moult discussed above, there are grey-brown sides to the breast, extending as a subtle differences in the pattern of the diffuse wash across the centre of the breast retained juvenile body feathers. The pale (sometimes, especially in adults, this can spots on retained juvenile feathers on the

662 British Birds 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers head, mantle and scapulars of Siberian Fly- preferred perch. Clearly these differences may catcher tend to be rather triangular (broadest count for nothing when encountering a at the tip of the feather), relatively small and vagrant on a treeless northern isle, but in have the dark part of the feather the same certain circumstances they can be helpful. colour as the replaced, adult-type feathers. In Grey-streaked these pale spots are also trian- Acknowledgments gular, but narrow towards the feather tip and I would like to thank Mark Adams at the British Museum of Natural History (Tring) for arranging access the dark part of the feather is subtly darker to the skin collection there. I would especially like to than the replaced, adult-type feathers. In thank Martin Hale, Michelle Wong and Peter Wong, Brown Flycatcher, the pale areas are distinctly whose excellent photos form the basis of this paper. rounded and the dark part of the feather is blackish and thus distinctly darker than References replaced adult-type feathers. Alström, P., & Hirschfeld, E. 1991. Field identification of Brown, Siberian and Grey-streaked Flycatchers. Birding World 4: 271–278. Behavioural differences Bradshaw, C., Jepson, P. J., & Lindsey, N. J. 1991. Siberian and Grey-streaked Flycatchers tend Identification of brown flycatchers. Brit. Birds 84: to select conspicuous perches (often higher 527–542. Harvey, P. 2010. Brown Flycatcher on Fair Isle: new to up in the tree canopy), and Siberian has a Britain. Brit. Birds 103: 651–657. very conspicuous habit of frequently Hudson, N., and the Rarities Committee. 2009. returning to one preferred perch when for- Report on rare birds in Great Britain in 2008. Brit. Birds 102: 528–601. aging. Brown Flycatcher will often forage at a Vaurie, C. 1959. The Birds of the Palearctic Fauna: lower level and choose less conspicuous a systematic reference. Order Passeriformes. perches when feeding. Brown also undertakes Witherby, London. shorter foraging flights than Grey-streaked Wingate, D. B. 1983. A Record of the Siberian Flycatcher (Muscicapa sibirica) from Bermuda: an and, especially, Siberian; the latter will often extreme extra-limital vagrant. Auk 100: 212–213. take long, rather acrobatic flights, which http://elibrary.unm.edu/sora/Auk/v100n01/ further emphasises the habit of returning to a p0212-p0213.pdf

Paul J. Leader, c/o Asia Ecological Consultants, 127 Commercial Centre, Palm Springs, New Territories, Hong Kong Alan Harris Brown Flycatcher Muscicapa dauurica

British Birds 103 • November 2010 • 658–671 663 Leader , Hong Kong, China, Hong Muscicapa Kong, dauurica , First-winter Brown First-winter Flycatcher Brown Michelle & Peter Wong Wong Michelle & Peter 362. 13th October 2007. Note the grey-toned upperparts, shortNote 13th the October primaryupperparts, grey-toned 2007. projection, conspicuous whitish (but eye-ring pale extensively not lores, prominent in front The bill with of is a the large, and conspicuous eye) rather neat head pattern. base yellow to the mandible. lower , Hong Kong, China, China, Hong Muscicapa Kong, dauurica , First-winter Brown First-winter Flycatcher Brown 361. Martin Hale 6th September 2006. A individual well-marked showing a sullied wash brown to the centre and similar sides to of some the Siberian breast, Flycatchers lacking apparently eye-ring note the pale extensively lores, However, sibirica . M. neat in head front of pattern the and eye, pale extensively mandible. lower

664 British Birds 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers , Perak, Malaysia, 4th Malaysia, Perak, Muscicapa dauurica , Adult Brown Adult Flycatcher Brown Lean Yen Loong Yen Lean 364. September 2003. adults a have complete moult After and breeding, appear Although this individual shows broad whitish fresh during autumn migration. fringes to the tertials that extend it onto lacks the the inner hook web, along the feather shaft characteristic of first-winter birds. Also note the less well- defined fringes to the greater coverts compared with the first-winter birds in plates 360 & 362. , Hebei province, China, 12th China, Hebei Muscicapa province, dauurica , Adult Brown Adult Flycatcher Brown 363. May 2005. In spring, adults and a appear have tendency In worn and to spring, abraded, be 2005. May They are still aged readily by the uniform rather than above. grey-toned brown, appearance and to the fringes the narrow to which greater coverts, the tertials, lack the hook extending back along the shaft characteristic of first-winter birds. show tertial this like fringes adult, that Some, are paler than the greater-covert This bird has rather limited pale feathering on fringes. the lores for this species, yet note that the in eye-ring front of the remains eye difficult to discern. Ran Schols

British Birds 103 • November 2010 • 658–671 665 Leader , Hong Muscicapa Kong, sibirica , Juvenile/first-winter Siberian Juvenile/first-winter Flycatcher Martin Hale 366. 18th September 2006.China, the this remnants of time juvenile Again, plumage, Note also well-defined the on are obvious. largely the dark underparts, lores, and the broadening behind eye-ring poorly the defined eye, submoustachial which combine stripe, to give this species hooded its appearance; rather dark, The and rather the delicate dark bill markings with on a the undertail-coverts. limited pale base to the mandible lower is typical for this species. M. dauurica .M. The , Hong Muscicapa Kong, sibirica , Juvenile/first-winter Siberian Juvenile/first-winter Flycatcher pale portion of the retained juvenile feathers on the scapulars is triangular and which Note is broadest at also narrow the feather prominent eye-ring, tip. in front of the and eye clearly broader behind. 365. China, 15th October 2005. Note 15th the October retained juvenile 2005. plumage China, on the head, which rump is and typical flanks, of scapulars, first-year Siberian in autumn. The primary projection is obviously longer than the and visible the tertials, tail looks short relatively when compared with Flycatcher Brown Michelle & Peter Wong Michelle & Peter

666 British Birds 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers , Hong Kong, China, 19th China, Hong Muscicapa Kong, sibirica , First-winter Siberian Flycatcher Michelle & Peter Wong Michelle & Peter October 2007. This bird has Note completed the its moult post-juvenile moult. October 2007. contrast between the two replaced (and rather uniformly plain) adult-type innermost greater coverts which and are the remaining juvenile greater coverts, conspicuously pale-edged and warmer-toned. This bird shows the classic dark, ‘hooded’ appearance of Siberian Flycatcher and the long primary projection – slightly longer than the wingtips exposed almost with tertials, level the tip of uppertail-coverts.the longest bill all small looks dark on this The view. obviously 368. , Hong Muscicapa Kong, sibirica , Juvenile/first-winter Siberian Juvenile/first-winter Flycatcher 367. China, 18th September 2006 China, (same individual as Note in the plate 366). retained juvenile feathers well- among the the largely dark upperparts, lores, This individual shows defined small, and eye-ring the long primary projection. ‘hooks’ to the blunt tips of the greater coverts and tertials. Martin Hale

British Birds 103 • November 2010 • 658–671 667 Leader in plate 376. in plate 376. M. griseisticta M. , Hong Kong, China, 1st May China, Hong Muscicapa Kong, sibirica , Adult Siberian Flycatcher Michelle & Peter Wong Michelle & Peter 370. Note the extensive streaking 2007. to and the compare with underparts, the underparts Flycatcher of the Grey-streaked M. dauurica M. , Hong Kong, China, Hong Muscicapa Kong, sibirica , First-winter Siberian Flycatcher 19th October 2007. Superficially 19th similar October to 2007. the Flycatcher Brown but in compare the plate reduced 361, pale well-defined area on the lores, (including eye-ring the in poorly defined front of submoustachial the eye), stripe and the dusky streaking to the centre of the breast. 369. Michelle & Peter Wong Michelle & Peter

668 British Birds 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers , Hong Muscicapa Kong, griseisticta , in plate 365. The wings and primary projection are clearly M. sibirica M. First-winter Grey-streaked Flycatcher First-winter Grey-streaked 372. Michelle & Peter Wong Michelle & Peter China, 1st October 2007. Note 1st the October well-defined streaking 2007. on China, the underparts, and diffuse retained juvenile streaking feathering on on the the crown, scapulars Compare the and shape of uppertail-coverts. the pale area on the scapulars (which is triangular but tapers towards the feather tip) with that of the Siberian Flycatcher and the very tail long, the projection (beyond wing-tip) is short. The large bill lacks an obvious pale base to the mandible. lower , Hong Kong, China, China, Hong Muscicapa Kong, sibirica , Adult Siberian Flycatcher Martin Hale 371. 15th October 2009. Compare the 15th rather October sullied 2009. underparts of this bird with those of individual the in more-streaked plate 370. Also note the uniformity of the head pattern and and the the dark greater coverts, marks on the undertail-coverts.

British Birds 103 • November 2010 • 658–671 669 Leader , Hong Muscicapa Kong, griseisticta , First-winter Grey-streaked Flycatcher First-winter Grey-streaked Michelle & Peter Wong Michelle & Peter 374. China, 6th May 2003. As well as note the the well-defined underpart streaking, 6th 2003. May China, mainly dark and bill. large, well-defined lateral throat stripe eye-ring, narrow , Hong Muscicapa Kong, griseisticta , First-winter Grey-streaked Flycatcher First-winter Grey-streaked Michelle & Peter Wong Michelle & Peter 373. China, 7th October 2007.China, The primary projection is conspicuously longer than the length of the and exposed the tertials; head pattern very similar to that of the first-winter in plate 374.

670 British Birds 103 • November 2010 • 658–671 Brown, Siberian and Grey-streaked Flycatchers , Hong Kong, China, Hong Muscicapa Kong, griseisticta , Adult Grey-streaked Flycatcher Adult Grey-streaked 1st October 2007. Note 1st the October diffuse 2007. pale fringes to the greater coverts. Michelle & Peter Wong Michelle & Peter 376. , Hong Kong, China, Hong Muscicapa Kong, griseisticta , , so the is dauuricaeye-ring , well defined. M. Adult Grey-streaked Flycatcher Adult Grey-streaked 1st October 2007. Note 1st the October the long 2007. diffuse primarypale fringes projection, to the greater and coverts and the tertials, diffuse streaking to the crown. While the this some lores is clearly have pale not feathering, as extensive as in Brown Flycatcher 375. Michelle & Peter Wong Michelle & Peter

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