Wanted: Your Sound Recordings of Leaf Warblers

Per Alström, Trevor Price, and Pratap Singh are studying song evolution in the leaf warbler family (Phylloscopidae). To understand how different song traits have evolved, the scientists plan to analyze vocalizations of all the species of leaf warbler and map their song parameters and calls on their molecular phylogeny.

The team is analyzing whole songs of all the species for size of song repertoire and singing variety. They need long song recordings, particularly for species having large repertoires.

For each species, Alström, Price, and Singh need 10 long recordings. They lack material for the following species:

Sulphur-bellied Warbler Phylloscopus griseolus
Ijima’s Leaf Warbler Phylloscopus ijimae
Kolombangara Leaf Warbler Phylloscopus amoenus
Smoky Warbler Phylloscopus fuligiventer
Black-capped Woodland Warbler Phylloscopus herberti
Red-faced Woodland Warbler Phylloscopus laetus
Laura’s Woodland Warbler Phylloscopus laurae
Makira Leaf Warbler Phylloscopus makirensis
Plain Leaf Warbler Phylloscopus neglectus
Alpine Leaf Warbler Phylloscopus occisinensis
Timor Leaf Warbler Phylloscopus presbytes
Pallas’s Leaf Warbler Phylloscopus proregulus
Sulawesi Leaf Warbler Phylloscopus sarasinorum
Siberian Chiffchaff Phylloscopus (collybita) tristis
Yellow-breasted Warbler Phylloscopus montis
Brooks’s Leaf Warbler Phylloscopus subviridis
Hainan Leaf Warbler Phylloscopus hainanus
Two-barred Warbler Phylloscopus plumbeitarsus

Can you share your recordings of the species above?

Alström et al. prefer uncompressed WAV files but will accept mp3’s. Please make clear the species in your recording. Your contribution will be acknowledged in the publication the team is preparing.

Attach your sound-recordings to an email and send it to Alström, Price, and Singh:

Per Alström
Swedish University of Agricultural Sciences
Per.Alstrom@slu.se

Trevor Price
Department of Ecology and Evolution
University of Chicago, USA
pricet@uchicago.edu

Pratap Singh
Wildlife Institute of India
Dehradun, India
pratapsingh6019@gmail.com

Featured image: An international team of scientists is calling on birders to provide sound-recordings of leaf warblers. Pictured here are five of the species for which recordings are needed. Clockwise from top L: Sulphur-bellied Warbler Phylloscopus griseolus, Alpine Leaf Warbler P. occisinensis, Smoky Warbler P. fuligiventer weigoldi, Pallas’s Leaf Warbler P. proregulus, and Hainan Leaf Warbler P. hainanus. (Craig Brelsford)

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Mysterious Yellow Wagtail at Cape Nanhui, Shanghai

Found at Shanghai’s Cape Nanhui on 1 May 2019: possible White-headed Yellow Wagtail Motacilla flava leucocephala. The discovery by Haiming Zhao provoked excitement and uncertainty among Shanghai birders. Certain aspects of the wagtail, notably the pale mottling on its mantle, cast doubt on an identification of White-headed. “Those pale/odd-looking feathers are unusual for leucocephala,” said Gomboo Sundev, a bird-tour leader in Mongolia, where leucocephala breeds. “I have never seen such an individual of the subspecies in Mongolia” (in litt., 2019).

Beijing-based British birder Paul Holt also noted the anomaly: “I was surprised … by the Shanghai bird’s mottled mantle” (in litt., 2019). Per Alström, co-author of Pipits and Wagtails, called the pale feathers on the mantle and scapulars “puzzling” (in litt., 2 May 2019). Both experts noted the pale base to the lower mandible of the Shanghai wagtail, also unexpected in leucocephala.

Students of Yellow Wagtail will not be surprised by the uncertainty. The Yellow Wagtail complex is a “systematic conundrum”; the various subspecies of the complex often “defy separation under the biological species concept” (Tyler 2004, 689). Interbreeding of the various subspecies occurs “freely at overlap zones, producing fertile hybrids” (689), often making it the case that “the direct parentage of Yellow Wagtails cannot be deciphered” (725). There is furthermore the prospect of partial albinism, a phenomenon that can make other subspecies of Yellow Wagtail appear white-headed (Alström & Mild 2003, 80, 269, 282).

In the case of leucocephala, another reason for the uncertainty is the sheer lack of knowledge about the race, even among elite ornithologists. Holt describes White-headed Yellow Wagtail as a “poorly known subspecies” (2019); Alström says his experience with the race is limited to “a few specimens and only one live bird” (in litt., 7 May 2019); Sundev told me he has seen the subspecies only about a dozen times (2019). The lack of information forces even great birders such as Holt to speculate: “The million-dollar question is whether [the mottled mantle and pale basal half of the lower mandible of the Shanghai bird] fit within the range of variation in leucocephala, or are they suggestive or even indicative of less than thoroughbred genes?” (2019)

Why is so little known about leucocephala? The biggest reason is the remoteness of its breeding range. White-headed Yellow Wagtail breeds in sparsely populated northwestern Mongolia, at places such as Khar-Us Lake (48.083328, 92.541368) and Durgun Lake (47.673106, 93.451188) (Sundev 2019). Alström and Mild say the race breeds also in areas adjacent to northwestern Mongolia, such as the Tuva Republic of Russia and “probably … northernmost Xinjiang” (2003, 281). Even the wintering range is uncertain; Alström and Mild say leucocephala “probably winters mainly in India but the exact wintering grounds are not known” (281).

The verdict on the Shanghai wagtail? “I would say it is leucocephala,” Sundev said. Holt agreed: “I would think that these [a White-headed Yellow Wagtail found in Hong Kong in April and the Shanghai wagtail] are the first two records of leucocephala for the whole of eastern China.” Alström, however, was less than fully convinced: “I’m not aware of a leucocephala with such a pale-mottled mantle as the Shanghai bird—although I can’t say they don’t occur” (7 May 2019).

PHOTOS

wagtail
L: The unusual Yellow Wagtail seen at Cape Nanhui, Shanghai on 1 May 2019. Note the pale mottling on the mantle. R: White-headed Yellow Wagtail Motacilla flava leucocephala, Mongolia. (L: Haiming Zhao; R: Gombobaatar Sundev)
wagtail
‘The encounter with the Western Yellow Wagtail was totally unexpected,’ said Shanghai birder Haiming Zhao, who discovered and photographed the bird. ‘The location where I found the bird is in a big area in Nanhui which has many trees newly planted. I came across this Western Yellow Wagtail when I went by this area searching for buntings. I was in my car looking at the ground 10-15 meters away to the left when I saw this special bird. Its bright gray head and yellow lower body were so eye-catching and had made it easily distinguished out there from a flock of eastern yellow wagtails on the ground’ (Zhao in litt., 2019). (Haiming Zhao)
wagtail
White-headed Yellow Wagtail on the breeding grounds in northwestern Mongolia. (Gombobaatar Sundev)

BIBLIOGRAPHY

Alström, P. (2019). Email to author, 2 May.

Alström, P. (2019). Email to author, 7 May.

Alström, P., Mild, K., & Zetterström, B. (2003). Pipits and Wagtails. Princeton University Press.

Holt, P. (2019). Messages to WeChat group Shanghai Birding, 1 May.

Sundev, G. (2019). Emails to author, 3 May.

Tyler, S.J. (2004). Family Motacillidae (Pipits and Wagtails). Pp. 689, 725 in del Hoyo, J., Elliott, A. & Christie, D.A. eds. (2004). Handbook of the Birds of the World. Vol. 9. Cotingas to Pipits and Wagtails. Lynx Edicions, Barcelona, Spain.

Zhao, H. (2019). Text messages to author, 2 May.

Featured image: Mysterious Yellow Wagtail, possibly White-headed Yellow Wagtail Motacilla flava leucocephala, Cape Nanhui, Shanghai, 1 May 2019. (Haiming Zhao)

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Per Alström Interviewed on Radio Beijing International

Per Alström
Per Alström

Whether they know it or not, all birders, Chinese or foreign, operating in China have been influenced by Per Alström. Radio Beijing International interviewed Per in November 2018. In the interview, Per talks about speciation, taxonomy, his early interest in birds, and his difficult and ground-breaking initial expeditions to China in the 1980s. Get to know this friendly giant of birding by listening to the interview below (23:56; 13 MB).

The image above shows some of the species that the Swedish ornithologist has either discovered or redefined. Clockwise from top left: Emei Leaf Warbler Phylloscopus emeiensis, Spotted Elachura Elachura formosa, Sichuan Bush Warbler Locustella chengi, and Alström’s Warbler Phylloscopus soror (Per Alström).

I have known Per since 2013. In the Dulong Gorge in Yunnan in 2014, I played a small part in Per’s discovery of yet another species, Himalayan Thrush Zoothera salimalii.  I wrote about the experience in a 2016 post, “A Minor Role in a Major Discovery.”

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Kamchatka Leaf Warbler in Shanghai

Seen at Pudong’s Cape Nanhui on Sun. 4 June 2017: Kamchatka Leaf Warbler Phylloscopus examinandus. Veteran British birder Michael Grunwell and I found our 4 Kamchatkas in Microforest 4 (30.953225, 121.959083), the largest of the tree plantations on the landward side of the sea wall. The species is an all-time first for the Shanghai eBird list.

Just after sunrise, Michael and I, as is our wont, were doing “drive-by birding”creeping along the edge of the road, listening out for birds. Suddenly, I heard an unfamiliar sound.

My gut said, “Hard, loudTaiga Flycatcher?”

Taiga was not even close, of course. Note, however, what my gut was not saying: “Arctic Warbler,” a bird whose call I know well. This call was decidedly not an Arctic’s, though it soon dawned on us that we were hearing some type of leaf warbler.

To see why my gut did not say Arctic, compare my recordings of the tight “tzit” call of Arctic Warbler with the looser call of Kamchatka Leaf Warbler:

Arctic Warbler Phylloscopus borealis, Yangkou-Rudong, Jiangsu (32.560095, 121.041956), 16 May 2015 (00:09; 1.9 MB)

Kamchatka Leaf Warbler P. examinandus, Microforest 4 (30.953225, 121.959083), Cape Nanhui, 4 June 2017 (00:25; 4.9 MB)

Michael and I skidded to a stop and poked our heads into the green tangle of locust trees. The call was being followed by a song. Only upon hearing the song did I think of Arctic Warbler. But here too, the song, though similar, was distinctive—wavier than the straight trill of Arctic. Look at the spectrograms below.

Spectrogram

The spectrogram above is of my recording 4 June 2017 of Kamchatka Leaf Warbler. Note the pattern: downward sweeps followed by an upward sweep. No one would liken that song to an insect’s. Below, the spectrogram of my 2015 recording of the song of Arctic Warbler. Note the straight, cricket-like trill.

Spectrogram

Here are the recordings whose spectrograms are shown above:

Arctic Warbler, Yikesama National Forest, Hulunbeier, Inner Mongolia (52.150833, 121.465639), 16 July 2015 (01:00; 3.2 MB)

Kamchatka Leaf Warbler, Microforest 4, 4 June 2017 (00:48; 9.3 MB)

After hearing several song-call cycles, Michael, my more experienced partner, first said the words “Kamchatka Leaf Warbler.”

Michael has birded the Indonesian islands of Flores and Komodo, where Kamchatka Leaf Warbler winters. Michael said that, last winter, walking through the forests there, he heard dozens of times the call of P. examinandus.

“I know that call,” Michael said.

I whipped out my Olympus DM-650 voice recorder and recorded the calling and singing warbler. Meanwhile, we caught our first glimpse of the individual. It was clearly an “Arctic-type” leaf warbler.

What is an “Arctic-type” leaf warbler? An Arctic-type leaf warbler is a member of one of four closely related taxa divided among three species: Japanese Leaf Warbler Phylloscopus xanthodryas, Kamchatka Leaf Warbler P. examinandus, and Arctic Warbler P. borealis borealis and P. b. kennicotti.

map
Leaf-warbler expert and Shanghai Birding member Per Alström is the person most responsible for our current understanding of Arctic-type leaf warblers. Alström’s PDF, from which this page is taken, is a handy introduction to leaf warblers in China and is downloadable through shanghaibirding.com.

Arctic Warbler is by far the most widespread breeder in the complex. P. b. borealis breeds across northern Eurasia, from Scandinavia to northeast China and the Russian Far East. P. b. kennicotti breeds in western Alaska.

As their names suggest, Japanese Leaf Warbler breeds mainly in Japan (Honshu, Shikoku, Kyushu), Kamchatka Leaf Warbler mainly in the southern Kamchatka Peninsula (as well as on Hokkaido and Sakhalin and in the Kuril Islands).

In 2010 Shanghai Birding member Per Alström et al. proposed the current way of viewing the Arctic-type warblers. Previously, the taxon examinandus was putative, not even reaching the subspecies level; Alström and his team showed that examinandus, with its distinctive song and call, merits recognition not as a subspecies of Arctic Warbler but as a species in its own right.

Of the three Arctic-type species, Japanese Leaf Warbler most stands out, being on average yellower than the two others. Arctic and Kamchatka look much more alike.

There are, however, some slight differences. Kamchatka is said to have a “marginally longer bill, tarsi and tail” than Arctic (del Hoyo & Collar). Sure enough, the Kamchatka I photographed is long-billed. Take a look below.

warblers
Arctic Warbler (top) and Kamchatka Leaf Warbler. Both birds show the classic features of Arctic-type warblers, among them a long supercilium that does not reach bill base, a dark smudge on the lower mandible, and mottled ear coverts. Kamchatka is said to be slightly greener on average than Arctic, a description that these photos do not contradict. The bill of Kamchatka is also marginally longer than Arctic’s, and in these profile shots one notes the longer bill of the Kamchatka and the stouter bill of the Arctic. I would not suggest basing an Arctic-Kamchatka ID on plumage and bare parts. Plumage and bare parts can, however, enhance the quality of a song- or call-based ID. Top: South Lock (30.860073, 121.909997), Cape Nanhui, 13 May 2017. Bottom: Microforest 4 (30.953225, 121.959083), 4 June 2017. (Craig Brelsford)

Michael and I heard our loudest song and calls during that first, early morning encounter. However, we heard Kamchatka calling throughout the day.

Our new Shanghai record, combined with late-May and early-June records from nearby Zhejiang, suggests that in this region, once the wave of Arctics passes through around 15 May, Kamchatka Leaf Warbler may be the Arctic-type to look out for.

BIBLIOGRAPHY

Alström P., T. Saitoh, D. Williams, I. Nishiumi, Y. Shigeta, K. Ueda, M. Irestedt, M. Björklund & U. Olsson (2011). The Arctic Warbler Phylloscopus borealis—three anciently separated cryptic species revealed. Ibis 153:395-410. Available at https://www.shanghaibirding.com/wp-content/uploads/2019/04/Alstrom-et-al-2011-Arctic-Warblers-IBIS.pdf (accessed 18 Sept. 2019).

Brelsford, C. (2017). eBird Checklist: https://ebird.org/ebird/view/checklist/S37369822. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York, USA. (Accessed 18 Sept. 2019)

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Brelsford, Craig, moderator. Shanghai Birding, a WeChat group. Discussions with various birders, chief among them Hangzhou birder Cheng Qian, who had information about sightings of P. examinandus in Zhejiang. Beijing-based Swedish birder Jan-Erik Nilsén also provided timely advice. To join Shanghai Birding, in WeChat, friend Craig Brelsford (WeChat ID: craigbrelsford). In your friend request, please make it clear that you wish to join Shanghai Birding.

del Hoyo, J. & Collar, N. (2017). Kamchatka Leaf-warbler (Phylloscopus examinandus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona, Spain (retrieved from https://www.hbw.com/node/1343935 on June 10, 2019).

Jackett, N. (25 Feb. 2016). First Kamchatka Leaf Warbler recorded for Australian Mainland. eBird Australia: https://ebird.org/content/australia/news/first-recorded-kamchatka-leaf-warbler-for-australian-mainland/. eBird, Ithaca, New York, USA. ebird.org (accessed: June 10, 2019).

Featured image: Kamchatka Leaf Warbler Phylloscopus examinandus. On 4 June 2017 at Cape Nanhui, birders Michael Grunwell and Craig Brelsford found the individual pictured here and three others. (Craig Brelsford)

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Comparing Richard’s and Blyth’s Pipit

Editor’s note: With more and more birders operating in Shanghai, more and more vagrant birds are bound to be discovered. One possibility is Blyth’s Pipit (photo above, L), a species similar to our familiar Richard’s Pipit (R). In this post, I will teach you how to separate the two.

2016 has been an outstanding birding year in Earth’s largest city. Paddyfield Warbler/Manchurian Reed Warbler, seen at Pudong’s Cape Nanhui on 18 Dec., was the latest in a parade of rare visitors seen in Shanghai in 2016.

The reason for the surge in good records, I am convinced, is more birders with better skills communicating more effectively. I am proud to say that shanghaibirding.com and the Shanghai Birding WeChat group have played a role.

In the Shanghai area, one species that has not yet been reported is Blyth’s Pipit. Anthus godlewskii breeds mainly in Mongolia, occurs on passage in central China, and winters mainly in India, so any records here would be of extralimitals. It is just the sort of vagrant that a bigger and better birding community could discover here in Shanghai.

Comparison of pipits
Comparison of adult-type Richard’s Pipit Anthus richardisinensis‘ (1) and adult Blyth’s Pipit A. godlewskii (4). The population group A. r. ‘sinensis’ occurs in southeast China south of the Yangtze River. Structurally, ‘sinensis‘ is the smallest group in Richard’s, with proportions recalling Blyth’s. Note however the blackish centers to the median coverts (2, 3). In adult-type Richard’s (2), the centers are triangular and tinged rufous at the edges. In adult Blyth’s (3), the centers are squarish, less rufous-tinged, and more clear-cut. 1, 2: Nanhui, December. 3, 4: Hulunbeier, Inner Mongolia, July. (Craig Brelsford)

The key to getting a Blyth’s in Shanghai is paying attention to the many Richard’s Pipit that we see in the area. Anthus richardi is more or less a passage migrant in the Shanghai area and is recorded here regularly in spring and autumn. Some are present in winter; Elaine Du and I had a “sinensis” last week, the ID’ing of which led to this post.

flight song
More views of Blyth’s Pipit performing flight song, Inner Mongolia, July. In Pipits and Wagtails, Shanghai Birding member Per Alström et al. write that in flight, Blyth’s Pipit ‘often recalls one of the smaller pipits rather than Richard’s’ (237). Note however that Anthus richardi ‘sinensis,’ a population group within Richard’s Pipit often found in Shanghai, is structurally similar to Blyth’s. (Craig Brelsford)

Richard’s “sinensis” is very similar to Blyth’s, being best told by song, which is rarely heard in the Shanghai area. According to Per Alström et al., whose book Pipits and Wagtails is the authority on Palearctic and Nearctic pipits, the song of Blyth’s is “very characteristic and completely different from [that] of Richard’s” (242). During a trip in July 2015 to the Inner Mongolian prefecture of Hulunbeier, one of the few places in China where Blyth’s breeds, I recorded the song.

Blyth’s Pipit, flight song, recorded 22 July 2015 at a point (48.767866, 116.834183) near Hulun Lake, Inner Mongolia (2.1 MB; 00:32)

The calls of the two species also differ, but less markedly. The flight call of Richard’s is a common bird sound in Shanghai during migration season. The call of Blyth’s is similar enough to “cause problems even for some veteran observers” (Alström et al. 244). For Shanghai birders, even those unfamiliar with Blyth’s, a “Richard’s” with a strange flight call is worth your attention. Listen for what Alström et al. describe as a call “less harsh, softer and more nasal” than Richard’s (244). For reference, review the flight call of Richard’s:

Richard’s Pipit, flight call, Dishui Lake, Shanghai, 5 Feb. 2016 (00:01; 852 KB)

Regarding plumage, the most reliable differentiator of Richard’s and Blyth’s is the pattern of the median coverts. In Blyth’s, a typical adult-type median covert will show well-defined, squarish black centers. In Richard’s, the adult-type median coverts are less clear-cut, rufous-tinged, and triangular. Note that the fresher the plumage, the more reliable this differentiator is.

Another less reliable criterion is structure. Shanghai birders will agree that the first impression a non-“sinensis” Richard’s usually gives is “large pipit.” Other pipits, such as Buff-bellied Pipit, Red-throated Pipit, and Olive-backed Pipit, give a “small pipit” impression.

Richard's Pipit
Richard’s Pipit, Yangkou, Jiangsu, September. Alström et al. urge care in ID’ing Blyth’s and Richard’s. Here, the median coverts of this Richard’s appear squarish, like Blyth’s (bottom R, inset). But note the date of the photo: September, a time of year when most Richard’s show worn plumage. ‘In worn plumage,’ the authors write, ‘the shape of the dark centres to the secondary coverts is generally less obviously different, and the pale tips can be much the same colour in both species’ (237). The ID of this Richard’s was derived from its call, a more constant characteristic, and not from the appearance of its median coverts, a more variable characteristic. (Craig Brelsford)

Alström et al. say, and I having seen Blyth’s can concur, that a birder viewing Blyth’s will get a “small pipit” impression: “The smaller size, lighter build and shorter tail,” the authors write, “are often most apparent in flight, when [Blyth’s] often recalls one of the smaller pipits rather than Richard’s.” Note also that the smaller size and shorter bill, tail, and hind claw of Blyth’s give that species a “better proportioned” look than the larger and heavier Richard’s (237).

The directions above should be seen as guidelines; individual Richard’s and Blyth’s may defy easy categorization, “sinensis” Richard’s even more so. Alström et al. caution against jumping the gun with your ID: “It is crucial to realise that in both species (especially Richard’s) appearance can vary considerably in one and the same individual depending on mood, weather, etc.,” they write. “Also, some Richard’s are structurally very like Blyth’s; this is especially true of southern Chinese Richard’s (‘sinensis’)” (237).

A record of Blyth’s Pipit in Shanghai would shoot to the top of the “Year’s Best” list. The stakes are high, so look diligently, and use caution. Good luck!

BIBLIOGRAPHY

Alström, Per, Krister Mild & Bill Zetterström. Pipits and Wagtails. Princeton University Press, 2003. This landmark book, co-authored by Shanghai Birding member Per Alström, is my first reference on all things Motacillidae.

Brazil, Mark. Birds of East Asia. Princeton University Press, 2009. Serviceable descriptions of Blyth’s Pipit and Richard’s Pipit. Illustration of “sinensis.”

Svensson, Lars & Killian Mullarney & Dan Zetterström. Collins Bird Guide, 2nd ed. HarperCollins, 1999-2009. Outstanding illustrations of Richard’s Pipit and Blyth’s Pipit by Mullarney.

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Pale-legged Leaf Warbler & the Shanghai Big 5

The illustration above shows Shanghai’s Big 5 Leaf Warblers: Pale-legged Leaf Warbler (1), Arctic Warbler (2), Eastern Crowned Warbler (3), Pallas’s Leaf Warbler (4), and Yellow-browed Warbler (5). In this post, I tell you how to separate Pale-legged and its lookalike Sakhalin Leaf Warbler from the others.

Recently at Cape Nanhui, the birding hotspot in Pudong, my object of observation was Pale-legged Leaf Warbler, one of the Big 5 Leaf Warblers in Shanghai. In both spring and autumn, Phylloscopus tenellipes passes through Earth’s greatest city in considerable numbers. A lookalike species, Sakhalin Leaf Warbler P. borealoides, also has been noted in Shanghai.

In this post, I shall outline the difficulty of distinguishing Pale-legged Leaf Warbler from Sakhalin Leaf Warbler on anything but call and song, and I will show you some of the traits of “Pale-Sak” that set this species pair apart from other leaf warblers.

SONG CAN SAFELY SEPARATE PALE-LEGGED FROM SAKHALIN

Per's PDF
‘Almost identical’: that’s the judgment of leaf-warbler expert Per Alström on Pale-legged and Sakhalin Leaf Warbler (regarding their plumage and bare parts). The page shown here is No. 11 of a 40-page PDF on leaf warblers in China by Professor Alström. The PDF is a handy introduction to a difficult group and can be downloaded here (13 MB).

Pale-legged Leaf Warbler is safely separable from Sakhalin Leaf Warbler only by song and call. Every other trait of each can occur in the other. Numerous authorities confirm this. Swedish ornithologist Per Alström calls the two species “almost identical” and “virtually indistinguishable except by song” (Alström 2012). Mark Brazil says field separation of Pale-Sak is “uncertain,” and he warns readers to “beware light conditions” (2009). Clement writes that Pale-legged and Sakhalin are “very similar” and claims, dubiously, that the latter is distinguishable from the former “mainly by greener upperparts and lack of wingbars” (2006). Clements goes on to describe juvenile Pale-legged as being “more greenish on upperparts,” which begs the question of whether the greenish Pale-Sak one is observing is an adult Sakhalin or a juvenile Pale-legged. Moreover, a quick look at Oriental Bird Images shows many Sakhalin Leaf Warbler with wing bars.

Thankfully for us birders, the songs of the two species are distinctive and provide the basis for a safe ID. The song of Pale-legged, occasionally heard in Shanghai in May, is a cricket-like trill, that of Sakhalin a high-pitched, three-note whistle.

Pale-legged Leaf Warbler, Boli County, Heilongjiang, 10 June 2016 (02:00, 6.4 MB)

Sakhalin Leaf Warbler, Zhongshan Park, Shanghai, 5 May 2016 (00:36; 2.2 MB)

One day last May, I heard Pale-legged and Sakhalin singing together in Zhongshan Park—proof that Sakhalin passes through Shanghai. Usually, however, birders here are forced to perform the less than satisfying task of assigning the individuals they see to the category “Pale-legged/Sakhalin Leaf Warbler.”

Bottom line: In Shanghai, any Pale-Sak one sees is probably Pale-legged Leaf Warbler, the continental breeder, and not Sakhalin Leaf Warbler, the breeder from the eponymous Russian island plus Hokkaido and Honshu; but to claim certainty about any non-singing individual is the taxonomical version of Russian roulette.

DISTINGUISHING PALE-SAK FROM OTHER LEAF WARBLERS

The Pale-Sak species pair is readily distinguishable from other leaf warblers, in particular the other four members of Shanghai’s Big 5: Pallas’s Leaf Warbler Phylloscopus proregulus, Yellow-browed Warbler P. inornatus, Arctic Warbler P. borealis, and Eastern Crowned Warbler P. coronatus.

Here are a few principles:

Pale-legged Leaf Warbler and Sakhalin Leaf Warbler are plain, mid-sized to large leaf warblers without even the hint of a coronal stripe.

Pale-legged/Sakhalin
Pale-legged/Sakhalin Leaf Warbler shows no trace of a crown stripe (Panel 1). Yellow-browed Warbler (2) usually shows a faint stripe. In Eastern Crowned Warbler (3) and Pallas’s Leaf Warbler (4), the stripe is prominent. (Craig Brelsford)

Pale-legged/Sakhalin Leaf Warbler has distinctive pink legs and a short bill with a black smudge on the lower mandible, which is pink at the base and tip.

warblers
Like Pale-legged/Sakhalin Leaf Warbler, species in the Arctic Warbler Complex lack a crown stripe and usually show one or two wing bars. One way to distinguish birds from the two groups is by the color of the legs and bill. The legs (Panel 1) of Pale-legged/Sakhalin Leaf Warbler are distinctively pale and pink, in contrast to the brownish-yellow legs of the Arctic-type Warbler in 2. Likewise, the slightly shorter bill of Pale-legged/Sakhalin (3) shows a blackish upper mandible and pinkish lower mandible and cutting edge. The black smudge on the lower mandible does not reach the tip. The bill of Arctic-type Warbler (4) follows a similar pattern, but with brownish-yellow replacing pink. (Craig Brelsford)

Even on a fast-moving Pale-Sak in poor light, the pink of the bill and especially of the legs is readily seen. The distinctive pale color of these bare parts is a handy tool for distinguishing Pale-Sak from birds in the Arctic Warbler Complex, which like Pale-Sak lack a crown stripe and usually show one or two wing bars. (The Arctic Warbler Complex consists of Arctic Warbler Phylloscopus borealis, Kamchatka Leaf Warbler P. examinandus, and Japanese Leaf Warbler P. xanthodryas. In Shanghai, Arctic Warbler is the most common of the three, migrating through Shanghai every spring and autumn.) The pink coloration also distinguishes Pale-Sak from Dusky Warbler P. fuscatus, an uncommon migrant and winter visitor in Shanghai, and the scarce passage migrant Two-barred Warbler P. plumbeitarsus.

Pale-legged/Sakhalin Leaf Warbler constantly pumps its tail.

tail
The tail of Pale-legged/Sakhalin Leaf Warbler pumps independently of other muscular actions. In panels 1-2, note that the tail pumps even as the warbler devours an insect. Panels 3-4 show the warbler motionless except for the up-and-down movement of the tail. Photos here and immediately below are of a single individual and were taken in September at Microforest 4 (30.953225, 121.959083), Cape Nanhui. (Craig Brelsford)

The tail-pumping of Pale-legged/Sakhalin is one of the most distinctive behavioral traits of the species pair. The steady movement usually occurs independently of other muscular actions and is slow enough for the eye to see. The tail-flicking of Arctic Warbler, by contrast, is more spasmodic and is often accompanied by wing-flicking.

Pale-legged/Sakhalin Leaf Warbler is often found on the lower, thicker branches of trees.

Pale-legged/Sakhalin Leaf Warbler
Pale-legged/Sakhalin Leaf Warbler on thick branch. More so than other leaf warblers, Pale-Sak is likely to be seen on leafless, thick branches low on the tree. (Craig Brelsford)

With its ability to forage along thick branches and not just glean from the underside of leaves, Pale-legged/Sakhalin can remind one of a nuthatch. Other species such as Arctic Warbler use the lower branches, but sustained observation shows Pale-Sak more often in those areas. Note: In May and June 2016, I studied Pale-legged Leaf Warbler on its breeding grounds in Heilongjiang. There, amid trees older and taller than one usually sees in Shanghai, I most often noted the species far above my head, in the mid-canopy.

A NOTE ON CALLS

Except for the mainly silent migrant Eastern Crowned Warbler, Shanghai’s Big 5 Leaf Warblers all call in both spring and autumn. The calls are distinctive. The metallic “tink” of Pale-Sak contrasts markedly with the “tzit” of Arctic Warbler, the “dweet” of Pallas’s Leaf Warbler, and the “sweet” of Yellow-browed Warbler.

Sakhalin Leaf Warbler, Nanhui, Shanghai, 8 May 2016 (00:15; 1.4 MB)

Arctic Warbler, Yangkou, Rudong, Jiangsu, 16 May 2015 (00:09; 1.9 MB)

Pallas’s Leaf Warbler, Yangkou, Rudong, Jiangsu, 9 May 2014 (00:05; 1.6 MB)

Yellow-browed Warbler, Lesser Yangshan Island, Zhejiang, 24 April 2014 (00:07; 1.7 MB)

Note that, according to Brazil, the call of Pale-Sak only can separate the pair from other species. It cannot be used to separate Pale-legged from Sakhalin. The tink of Pale-legged, Brazil writes, “is probably indistinguishable from Sakhalin Leaf” (2).

UPDATE

Editor’s note: This post caught the attention of Philip D. Round, a professor at Mahidol University in Bangkok and an expert on leaf warblers. In an e-mail to me, Round writes that as discoveries are made and papers published, separating Pale-legged Leaf Warbler from Sakhalin Leaf Warbler on call may become more widespread. Separation on morphology, by contrast, will be much more difficult, though it may eventually turn out to be possible in the hand.

The following paragraphs are from Round’s e-mail to me:

“I enclose a paper that details the first records of both Kamchatka Leaf Warbler and Sakhalin Leaf Warbler from Thailand. [Editor’s note: the paper, “Addition of Kamchatka Leaf Warbler Phylloscopus examinandus and Sakhalin Leaf Warbler P. borealoides to Thailand’s Avifauna,” is available for download through shanghaibirding.com (708 KB).] This has been rather overtaken by events, as we have now caught into the hundreds of Sakhalin LW, mostly on spring passage, and quite a few more Kamchatka. I have an undergraduate student who has carried out DNA assay on about ten percent of all the Pale-legged and Sakhalin LW caught. For many of these we have also recorded call notes on release. When she comes back from overseas study in January 2017 I hope we’ll get a paper out which publishes details of call-note frequency and DNA results for this large sample, which should show the correlation between species and call-note frequency clearly. (Actually this is moderately and anecdotally well-known already. I think either Frank Lambert or Jonathan Martinez was the first to draw my attention to the difference, and it is mentioned by Yap et al. in BirdingASIA with reference to an overwintering Singapore bird.) [Note: Round is referring to Yap, Francis et al., “First wintering record of the Sakhalin Leaf Warbler Phylloscopus borealoides in South-East Asia, with notes on vocalisations,” BirdingASIA 21 (2014): 76–81.]

“I am a bit less sanguine on finding means (other than by call frequency or song) to separate all birds. Even in the hand, it is by no means clear. We can pick out long-winged male Sakhalin, and short-winged female Pale-legged. But there is more overlap than previously realized, and most are in between. There don’t appear to be any 100% consistent wing-formula differences, and plumage and bare-part features, while somewhat indicative, are again less than 100% reliable—especially under field conditions. But probably we are missing something. The next thing to do is to apply PCA or some other multivariate analysis to figure out reliable means of separation of birds in the hand from our large sample, and also to use the information we have to figure out differences in the timing of passage of the two spp.”

BIBLIOGRAPHY

Alström, P. (2012). Identification of Phylloscopus & Seicercus Warblers in China. Notes from presentation given to Beijing Birdwatching Society in November 2012. PDF downloadable here (13 MB). Click here for a 5 MB zip archive containing all 40 pages of the report in JPEG form. Those pages can be synced to your smartphone like photographs and consulted in the field. (Accessed: 12 September 2019)

Brazil, M. (2009). Birds of East Asia. Princeton, New Jersey: Princeton University Press.

Clement, P. (2006). Family Sylviidae (Old World Warblers). Pp. 663-4 (Pale-legged Leaf Warbler, Sakhalin Leaf Warbler) in del Hoyo, J., Elliott, A. & Christie, D.A. eds. (2006). Handbook of the Birds of the World. Vol. 11. Old World Flycatchers to Old World Warblers. Lynx Edicions, Barcelona, Spain.

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Amazing Spring Records for Shanghai

The past 10 days have seen a parade of migrants passing through Shanghai. Grey-crowned Warbler and Blue Whistling Thrush shocked birders at Cape Nanhui. The birding site in southeast Pudong also yielded Pheasant-tailed Jacana, Pacific Golden Plover, Red Knot, Grey-tailed Tattler, Amur Paradise Flycatcher, singing Arctic Warbler, calling Two-barred Warbler, Radde’s Warbler, White-throated Rock Thrush, and still more Pechora Pipit. Tiger Shrike and Black Bulbul have been noted at Nanhui and on Lesser Yangshan, with the latter location yielding Peregrine Falcon and Rufous-tailed Robin singing from deep cover. Other interesting records were Red Turtle Dove, Black-winged Cuckooshrike, Hair-crested Drongo, Ashy Drongo, day counts as high as 21 of Black Drongo, a trio of Siberians (Siberian Thrush, Siberian Blue Robin, Siberian Rubythroat), plus Chestnut Bunting and endangered Yellow-breasted Bunting. Zhongshan Park yielded our season’s first singing Black-naped Oriole. My friend Kai Pflug was one of a group of birders who found Fujian Niltava at Nanhui, a first for Shanghai.

A White-throated Rock Thrush yawns at Nanhui, 17 May 2016. A pair of males set up shop in Microforest 1 and stayed all day.
A White-throated Rock Thrush yawns at Nanhui, 17 May 2016. A pair of males set up shop in Microforest 1 and stayed all day.

At this time of year, considering the richness of the Shanghai coast and the lack of birder coverage over the years, I go out not hoping, but expecting to get interesting records. Recently, I have rarely been disappointed.

GREY-CROWNED WARBLER, RARE IN SHANGHAI

Though I missed Kai’s niltava, the German birder brought me good luck in another way. On a spectacular Tues. morning 17 May at Nanhui, exploring the lush microforests, he and I found Grey-crowned Warbler Seicercus tephrocephalus.

Grey-crowned Warbler, Nanhui, 17 May 2016.
Grey-crowned Warbler, Nanhui, 17 May 2016.

The bird was singing, an amazing incongruity, the bright, sharp south-Chinese Seicercus sound here in a tiny wood on the muddy Chinese coast. The golden warbler alighted on a branch for several seconds. I got photos and a sound recording. Grey-crowned Warbler is rarely seen this far east and is not covered in Mark Brazil’s Birds of East Asia. However the very good Handbook of the Birds of the World Vol. 11, which I can’t recommend enough to lovers of leaf warblers and golden spectacled warblers, has the info we need.

A monotypic species, S. tephrocephalus is said by HBW 11 to breed closest to us in Hubei. It is very simliar in plumage and song to Martens’s Warbler S. omeiensis but unlike Martens’s has eye-ring broken at rear. S. tephrocephalus is common to abundant in its normal range of south China and Southeast Asia, but it has rarely if ever been recorded in Shanghai. The lack of records is owing not only to its scarcity but also to its difficulty in identification, particularly for birders unfamiliar with HBW 11.

One of the pages dedicated to Seicercus warblers. Taken from a well-known PDF created by Shanghai Birding member Per Alström for a presentation he made to the Beijing Birdwatching Society in 2012. This report is now downloadable through shanghaibirding.com. See nearby text for link.
One of the pages dedicated to Seicercus warblers. Taken from a well-known PDF created by Shanghai Birding member Per Alström for a presentation he made to the Beijing Birdwatching Society in 2012. The PDF is now downloadable through shanghaibirding.com.

Much of the wealth of info on Seicercus warblers in HBW 11 is the fruit of the research of Swedish ornithologist Per Alström, who wrote nearly all the Seicercus entries. Guangdong-based French birder Jonathan Martinez has also researched S. tephrocephalus and helped me with the ID of the Grey-crowned Warbler. Both are members of the Shanghai Birding WeChat group and are readers of shanghaibirding.com. Thanks to both of you for your contributions.

Here are the sound-recordings I made of Grey-crowned Warbler. The recordings and photos are of the same individual.

Grey-crowned Warbler 1/2, Nanhui, Shanghai, 17 May 2016 (00:11; 1.2 MB)

Grey-crowned Warbler 2/2, Nanhui, Shanghai, 17 May 2016 (00:23; 1.7 MB)

After viewing the photos and listening to the recordings, Per wrote the following to the Shanghai Birding chat group:

“Hi Craig. … I agree with your id of Grey-crowned Warbler, mainly based on the song recording (songs and calls are by far the best ways to id Seicercus warblers). The photos look a bit off (e.g., eye-ring broken in front, which isn’t normally the case in any Seicercus, seemingly poorly marked lateral crown-stripes, no clear grey on crown [though that could be a photo effect], and dark-tipped lower mandible [only in Grey-cheeked W]). Simple id tips, paintings and a few photos can be found on my research web page. In a PDF on leaf warblers from a talk for Beijing Birdwatching Society, there are also sound recordings of … Seicercus warblers on the same page.” (That very useful PDF is now available for download through shanghaibirding.com [13 MB]: Phylloscopidae-Beijing-Birdwatching-Society-nov-2012 English)

To sum up:

My research indicates, and Per Alström concurs: Grey-crowned Warbler (Seicercus tephrocephalus)

Grey-crowned has eye-ring broken at rear; my photos show eye-ring broken at rear. The songs I recorded most closely match the song of S. tephrocephalus.

Next-closest possibility: Martens’s Warbler (S. omeiensis)

Very similar to Grey-crowned Warbler but doesn’t have eye-ring broken at rear.

Also: Alström’s Warbler (S. soror); my recording has trills; distinctive song of Alström’s lacks trills. Bianchi’s Warbler (S. valentini) does not trill. White-spectacled Warbler (S. affinis intermedius) has eye-ring broken above eye, not behind.

BLUE WHISTLING THRUSH, ANOTHER RARITY IN SHANGHAI

Blue Whistling Thrush, Nanhui, 15 May 2016.
Blue Whistling Thrush, Nanhui, 15 May 2016.

A coastal record of Blue Whistling Thrush is rare; the species had not been recorded in Shanghai since 1987. The places closest to Shanghai where I’ve seen the species are Tianmu Mountains in Zhejiang and in Nanjing Zhongshan Botanical Garden. When on Sun. 15 May we first saw the glossy blue-black bird, my partners Jan-Erik Nilsén and Elaine Du and I were flummoxed. We lingered around microforests 3-8 at Nanhui, waiting to get another look. We finally got a second look and realized it was whistler.

Birders tend to think of Blue Whistling Thrush as the ultimate resident, a fixture along fast-flowing mountain streams. The bird is however at least partly migratory, as our record and observations of other birders prove. In a text message to the Shanghai Birding WeChat group, Jonathan Martinez wrote: “BWT are migrants; I used to have them annually in northern Hunan at a site not suitable for breeding.”

CUCKOOS ARE CALLING IN SHANGHAI!

Comparison of Indian Cuckoo and Common Cuckoo. Bottom-left cuckoo is Common; note yellow iris and compare to dark iris of Indian in bottom-right panel. Top two panels also Indian. All photos taken 17 May 2016 at Nanhui.
Comparison of Indian Cuckoo and Common Cuckoo. Bottom-left cuckoo is Common; note yellow iris and compare to dark iris of Indian in bottom-right panel. Top two panels also Indian. All photos taken 17 May 2016 at Nanhui.

One of the many reasons I love spring is that during this time cuckoos call and are easier to identify. On Tues. 17 May at Nanhui Kai Pflug and I had two calling cuckoos: Common and Indian. I got photos of both. Can you see differences in the appearance of Common and Indian? One is eye color. See four-panel photo for comparison. The other is the thickness of the barring on the underparts. Indian also is smaller than Common, but the size difference is harder to see.

Here is one of the best-known bird calls in the world, that of Common Cuckoo, recorded by me at Nanhui on 17 May (00:31; 2 MB):

OTHER NOTES

— More Nanhui notes from Tues. 17 May: 0 ducks, 0 raptors, and Dishui Lake contained a grand total of 3 birds, all Great Crested Grebe. Also, on a weekday, even though weather superb, tourists were few; Kai Pflug and I enjoyed blessed peace and quiet. It was as quiet as a rainy Saturday or Sunday. We were lovin’ that!

— On Tues. 17 May Kai and I found bird netting at “Dowitcher Pond” (30.877779, 121.955465) in Nanhui. Area is fenced in and netting was tied to posts in deep water, so removing it will be a challenge.

— Here is a recording I made of Arctic Warbler at Nanhui.

Arctic Warbler, “half-hearted” song, Nanhui, 17 May 2016 (00:38; 2.3 MB)

— Here is the sound of Rufous-tailed Robin singing on Lesser Yangshan. The robins were singing unseen on the thickly vegetated hillside above the tunnel entrance at Xiǎoyánglíng Cove (30.642243, 122.066940).

Rufous-tailed Robin singing from thick cover, Lesser Yangshan Island, 14 May 2016 (00:08; 1.1 MB):

— Thanks to our birding partners Michael Grunwell, Jan-Erik Nilsén, and Kai Pflug.

PHOTOS

Black-winged Cuckooshrike making use of microforest, Nanhui, 14 May 2016.
Black-winged Cuckooshrike making use of microforest, Nanhui, 14 May 2016.
Red Knot, Nanhui, 15 May 2016.
Red Knot, Nanhui, 15 May 2016.
Black-browed Reed Warbler, Nanhui, 17 May 2016.
Black-browed Reed Warbler, Nanhui, 17 May 2016.
Reed Parrotbill, Nanhui, 17 May 2016. This species gets my vote for Bird of the City of Shanghai. It's charismatic and beautiful, and as a reed-bed specialist, Reed Parrotbill underlines the need to preserve what remains of the reeds in Shanghai and elsewhere along the China coast.
Reed Parrotbill, Nanhui, 17 May 2016. This species gets my vote for Bird of the City of Shanghai. It’s charismatic and beautiful, and as a reed-bed specialist, Reed Parrotbill underlines the need to preserve what remains of the reeds in Shanghai and elsewhere along the China coast.

Featured image: Here’s a handy rule for bird photographers: When you have light conditions as good as those we had Tues. morning 17 May 2016, then shoot anything, even a sparrow. It’ll look good. Luckily I had this more interesting Common Cuckoo Cuculus canorus. I was at Cape Nanhui in Shanghai. Nikon D3S, 600 mm, F6.3, 1/5000, ISO 6400.

A Minor Role in a Major Discovery

Now my involvement in the discovery of Himalayan Thrush was on this wise:

In June 2014, my partners and I drove 36 hours, including one stretch of 24 straight hours, covering 1500 km (930 mi.) to get from Emeishan in Sichuan to the Dulong Gorge in Yunnan. The reason? Per Alström was in the Dulong Gorge and was working on an exciting project, a project to which he said I might be able to make a small contribution.

Himalayan Thrush
Himalayan Thrush Zoothera salimalii, Irrawaddy-Salween Divide, above Dulong Gorge, Yunnan, 20 June 2014. Elev. 3380 m (11,090 ft.). (Craig Brelsford)

We finally met up with Per and his team on the road into the Dulong Gorge. There, Per transferred to me a recording of a species new to science, Himalayan Thrush Zoothera salimalii.

Little did I know that I was on the cusp of something big.

At the time, I did not know that the species was Himalayan Thrush; like any normal birder, I took the species to be Plain-backed Thrush. Per could only divulge that he was working on possible splits to Plain-backed Thrush, and could I please try to get a shot of a free “Plain-backed”? All his images, he said, were of captured birds, and he wanted shots of birds living their natural life. “I’ll do everything I can to get those photos!” I said. Per then left the Dulong Gorge, and my team entered the valley.

Himalayan Thrush
Himalayan Thrush. Note the very slightly rufous-toned upper surface, dark lower lores and subocular/moustachial area, lack of distinct dark patch on rear ear-coverts, entirely dark lower mandible, hooked upper mandible, and pale, pinkish legs. (Craig Brelsford)

Rain rain rain for days. Finally, a 45-minute window of dry weather. I’m at the spot Per indicated, elev. 3380 m (11,090 ft.). I play Per’s recording. Attracted by the recording, a Himalayan Thrush appears within minutes, and I get photos as well as recordings of the thrush’s song. What a payoff!

Now my photos figure in the article Per and his co-authors have written on Himalayan Thrush, Sichuan Thrush Zoothera griseiceps, and Alpine Thrush Z. mollissima (Z. mollissima was formerly called “Plain-backed Thrush” in English but in the wake of the new discoveries takes the name Alpine Thrush). Himalayan Thrush is completely new to science, and Sichuan Thrush has been elevated to species status (having been considered a ssp. of Z. mollissima). A fourth putative taxon, “Yunnan Thrush,” requires further study.

I’m proud to have played a minor role in Per and co.’s major discovery!

Himalayan Thrush
Himalayan Thrush on a wet boulder in the rain above Dulong Gorge. A ‘forest’ thrush on a rocky outcrop? Yes, write the authors: ‘At Dulongjiang, Yunnan province, China, we found Himalayan Forest Thrush to be numerous in a very different habitat: on steep slopes with bamboo and rhododendron scrub and rocky outcrops and a few scattered conifers, at or just above the upper tree limit, at 3350–3500 m a.s.l. … Surprisingly, we did not observe any birds in the seemingly suitable forest immediately below despite active searching.’ (Craig Brelsford)

WHAT IS ‘NEW TO SCIENCE’?

In the case of Zoothera salimalii, when we say the species is “new to science,” we are not saying that no human being had ever seen the bird before. Himalayan Thrush is locally common in its range, which extends from Sikkim in India to northwest Yunnan; thousands of birders and non-birders have seen it. “New to science” means that those observers did not understand its true nature. We did not understand that it is a species; if we thought about it at all, we assumed that any Z. salimalii we were seeing was just another Plain-backed Thrush Z. mollissima.

Himalayan
From article: ‘Z. salimalii has a narrow, almost unmarked golden-buff throat (whiter when worn) bordered by strong black malar.’ Note our specimen’s buff throat and distinct malar. (Craig Brelsford)

Per and his team discovered that, hidden within what was considered to be a population of Z. mollissima was an entirely different bird, separated from Z. mollissima by time (3-5 million years of evolution), habitat (Z. mollissima Alpine Thrush breeds higher than Z. salimalii Himalayan Thrush), song, and morphology.

The latter two characteristics are particularly surprising and point to the difficulties of birding in the Himalayan region. Per and his team did not need a microscope to begin to see that Himalayan Thrush is different from the other species in the Plain-backed Thrush complex. All they needed to do was look and listen closely. Yet for generation after generation, this straightforward analysis was not performed. This is not surprising, considering the ruggedness of the area in which these thrushes live and its sparse population.

Himalayan Thrush
My Himalayan Thrush was fit and strong—as he needed to be, if he wanted to command his large, rocky territory. (Craig Brelsford)

Once Per had examined Plain-backed complex birds in the hand and through photos, he found a whole series of visible differences. Per et al. write:

Compared to Z. mollissima, Z. salimalii has a noticeably longer and deeper bill, with more arched culmen and longer hook, and the lower edge of the lower mandible is more arched (vs. straight); bill usually completely or almost completely dark including base of lower mandible, whereas the base of the lower mandible is usually pale pinkish or yellowish in Z. mollissima (though may appear mainly dark also in Z. mollissima).

Most individuals of Z. salimalii have a thin whitish supraloral stripe over thick blackish lores, and a very dark subocular/moustachial area, more or less connected to the dark lores, compared to more diffuse pale supraloral and weak “salt-and-pepper” lores and subocular/moustachial area of Z. mollissima. Also, Z. salimalii usually shows less extensively pale-mottled ear-coverts than in Z. mollissima, especially on the upper part, and lacks or has only a very ill-defined dark spot on the rear ear-coverts, while Z. mollissima usually shows a distinct dark rear ear-covert patch. Z. salimalii is usually ruddier in color above than Z. mollissima. Z. salimalii has a narrow, almost unmarked golden-buff throat (whiter when worn) bordered by strong black malar, while in Z. mollissima the throat is usually whiter and generally more heavily marked (often much more so) and less strongly bordered by more diffuse malar stripes. Z. salimalii has the claws paler than the toes, lacking dusky areas, while in Z. mollissima the claws are at least partly darker than or similar in color to the toes. The legs of Z. salimalii are pinkish, while those of Z. mollissima are usually brighter and more yellow- or orange-tinged.

Himalayan Thrush
Himalayan Thrush, Baihualing, Yunnan, 4 Feb. 2014. Baihualing is in the southern part of the Gaoligong Mountains. The elevation here is ca. 1800 m (5,900 ft.). (Craig Brelsford)

So adept became Per at discerning the morphological differences of the various Plain-backed species, he was able to determine, by photos alone, that a “Plain-backed” I had found in Yunnan in February 2014 was also Himalayan Thrush. Per used my February 2014 photos along with my June 2014 photos in his article.

The song of Z. salimalii also contrasts markedly with that of Z. mollissima, Per et al. write. They note the “mainly rasping, grating, scratchy, cracked voice” of Alpine Thrush and the “more musical … ‘thrush-like'” song of Himalayan Thrush. Indeed, according to the article, the germ of the process that led to the discovery of Himalayan Thrush was Per standing in India and simply listening to Himalayan Thrush, remembering the similar song he’d earlier heard in Sichuan of what is now called Sichuan Thrush, and contrasting those sweeter songs with the scratchier song of Alpine Thrush. Here we see Per, the scientist famous for discovering new species according to complicated DNA research, relying not on microscopes but on good old-fashioned birding skills!

Himalayan Thrush
Himalayan Thrush powerfully shovels away dirt, leaves, and sticks as it searches for invertebrates on the forest floor. (Craig Brelsford)

Below, some of my recordings and videos of Himalayan Thrush.

Sound Recordings, by Craig Brelsford

Video (all taken by Craig Brelsford at Baihualing, Gaoligong Mountains, western Yunnan, 4-5 Feb. 2014)

Featured image: Craig Brelsford (L), Craig’s partner Jon Gallagher, and Per Alström (R), above the Dulong Gorge in remote northwestern Yunnan, 13 June 2014. The insets show Himalayan Thrush Zoothera salimalii, which Per was there studying, and photos of which I later acquired. (Huáng Xiǎo Ān [黄小安])

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