Regarding the comment by Dr. Nial Moores in the shanghaibirding.com post Kamchatka Leaf Warbler in Shanghai (6 June 2017): I would agree that both Arctic Warbler Phylloscopus borealis and Kamchatka Leaf Warbler P. examinandus may come through late, alongside each other, even in mid- to late May.
Here in Thailand, I think our earliest Kamchatka (diagnosed on wing length, greater than 70 mm) was 14 April, caught on Man Nai Island (12.015924, 102.283475) at the same time (so far) as our only undoubted Japanese Leaf Warbler P. xanthodryas.
While on average Kamchatka may be slightly larger-billed, and the respective sexes larger and longer-winged than Arctics, there is not much in it. Anybody who expects to be able to call birds one or the other in the field on anything other than voice is stretching credibility, I feel. Plumage overlap seems total. And of course on body size and wing length there is overlap between male Arctic and female Kamchatka.
The featured image above shows two individuals, with two photos each. Both were freshly moulted birds caught on northwards spring passage at Laem Phak Bia (13.050000, 100.083333), Phetchaburi, Thailand. Both were picked out as being slightly more brightly yellowish on underparts and on supercilium than typical spring borealis (caught on the same day), and brighter green above.
The bird in panels 1 and 2 was caught 14 May 2011. Measurements were wing 66 mm, bill 14.5 mm. On mt DNA (COI) we determined that it was examinandus. The identically bright-coloured individual in panels 3 and 4 was caught on the same day. Measurements were wing 62 mm, bill 14.5 mm. It was borealis on DNA.
The paper of which this comparison was a part is titled “Addition of Kamchatka Leaf Warbler Phylloscopus examinandus and Sakhalin Leaf Warbler P. borealoides to Thailand’s Avifauna.” It was published by the Japan Bird Banding Journal and is downloadable (708 KB) through shanghaibirding.com.
We record Kamchatka annually in Thailand, with most records in May. On average it is a later migrant than Arctic with (old specimen) records from Thailand and Malaysia even into the last days of May. Based on birds handled (and DNA assayed), I would re-emphasise that there is total overlap on the range of plumage characters with borealis.
Though we selected our first, unusually bright-plumaged “Arctic Warblers” in mid-May for assay specifically because they were a bit more yellow-green than usual, note that, just as in the panels above, some turned out to be examinandus and some seemingly identically bright birds were borealis.
Takema Saitoh at the Yamashina Institute has a little module that uses a canonical discriminant function that will separate most birds on biometrics. But of course, this is only good for birds that are handled. The key parameters are wing length, total head length (head plus bill), length of outermost primary, and length of tarsus.
As Craig Brelsford notes in his 6 June post, Kamchatka on average are a bit longer-billed. But even this did not reliably separate all birds unless one knew the sex (problems of overlap between female Kamchatka and male Arctic).
Call and song–so important!
Editor’s note: shanghaibirding.com has a growing library of resources on leaf warblers. In addition to the paper Phil Round directs us to above, we have the excellent presentation by Per Alström, “Identification of Phylloscopus & Seicercus warblers in China,” downloadable here (13 MB).
Craig Brelsford has written the following posts about leaf warblers:
Seen at Pudong’s Cape Nanhui on Sun. 4 June 2017: Kamchatka Leaf WarblerPhylloscopus 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, loud–Taiga 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:
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.
After hearing several song-call cycles, Michael, my more experienced partner and the man who has taught me more than anyone about birding, 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.
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.
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.
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.
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.
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, fill out the form on the shanghaibirding.com Sightings page. Please state that you wish to join Shanghai Birding. You may also 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 http://www.hbw.com/node/1343935 on 6 June 2017).
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. Photos by Craig Brelsford.
Editor’s note: The photo above shows Hooded Crane flying above fields at Nanhui on 12 Nov. 2016. Before our sighting, Grus monacha had never been recorded on the Shanghai Peninsula. Each year, about 100 Hooded Crane overwinter on eastern Chongming Island, 60 km north of Nanhui at the mouth of the Yangtze River.
Elaine Du and I birded three of the four days between Sat. 12 Nov. and Tues. 15 Nov. 2016. We noted 105 species. On Saturday we had the first-ever record in Nanhui of Hooded Crane. We also found Baikal Teal on Saturday as well as Greater White-fronted Goose, Tundra Swan, and Jack Snipe. Sunday was also spent at the coastal site in Pudong and gave us calling Brown-cheeked Rail as well as Hair-crested Drongo and late Rufous-tailed Robin. Other weekend Nanhui records were EndangeredBlack-faced Spoonbill holding steady at the defunct nature reserve (30.920500, 121.973167), Amur Falcon feasting on gnats small enough for leaf warblers, an uncommon Shanghai record of Water Pipit, and two more sightings of EndangeredYellow-breasted Bunting at its increasingly reliable site (30.850707, 121.863662). On Tuesday at Shanghai’s Zhongshan Park (31.221888, 121.420066) we had a very late Narcissus Flycatcher.
ELAINE’S FEAT OF BIRDING
The flyby sighting of Hooded Crane was Elaine’s finest hour. Michael Grunwell was in the back seat and, blinded by the roof, would have never seen the crane. I was busy driving along a very uncertain dirt track. We see so many Grey Heron at Nanhui, and it is so easy to disregard them, and sure enough two of the three birds flying together were Grey Heron. But one was not, and Elaine caught it.
Elaine got her first pair of binoculars in 2013 and is now making big discoveries. “You’ve come a long way, baby!”
Thanks to Shanghai birder Xiao Cao for his knowledge of species histories in Shanghai. It was he who told us that our Hooded Crane was a first record for mainland Shanghai.
JACK SNIPE AT IRON TRACK
The experience with Jack Snipe occurred Saturday near dark at Iron Track (31.003613, 121.907883). Our partner Michael Grunwell, Elaine, and I were looking for Brown-cheeked Rail. The snipe sneezed when flushed, flew to a towering height in a tighter formation than is typical in Common Snipe, and after all the fuss ended up landing only 150 m from where they had started.
When the snipe began their flight, I figured they were Common and continued looking for rails. Then I heard Michael cry out, “Possible Jack!” The snipe flew directly over us. The bill was noticeably shorter than the bill of the Common I have come to know. Elaine too saw the short bill.
The three of us feel confident in our record of Jack Snipe and urge others to be on the lookout for this species. Get pictures if you can.
Iron Track is part of the extensive reed-bed habitat lining the Dazhi River (大治河). It provides excellent habitat for Chinese Pond Heron, White-breasted Waterhen, Brown-cheeked Rail (and possibly Water Rail), wintering Bluethroat, and wintering Jack Snipe. Reed Parrotbill is resident.
The beds are on either side of the river, are unlikely to be developed, and are in good condition. They are a remnant of the habitat that used to cover the entire area.
YELLOW-BREASTED BUNTING IN SHANGHAI
As reported above, on Saturday with Michael and yet again on Sunday our site near Luchao delivered Yellow-breasted Bunting. The site is at 30.850694, 121.863667. We are now five-for-five in sightings of Yellow-breasted Bunting since our Nov. 5 discovery of the species there.
It will be interesting to see how long into the winter the Yellow-breasted Bunting remain. I hope they stay awhile, because it is unlikely any of the locals will catch ’n’ roast ’em. (The greatest factor in the endangerment of Emberiza aureola is massive poaching of the species for snacks in south China.)
Recently the site has yielded Black-browed Reed Warbler and Chestnut-eared Bunting and a late record of Barn Swallow. An un-ID’d rail has been spotted twice in the area.
To get to the site, from Luchao drive 1.5 km north from the bend in the road north of the canal, where the road begins to run parallel with the sea. Pull onto the unpaved track and park on the bridge of white cement. The buntings seem to be concentrated a few dozen meters south, near the place where picnickers dumped a big load of trash. Be on the lookout for individuals flying into the narrow reed bed after foraging runs in the adjacent rice paddies.
ID’ING BROWN-CHEEKED RAIL ON CALL
On Sunday at Nanhui we positively identified 2 Brown-cheeked Rail on call. Here is the recording I made (00:28; 2.7 MB):
The pitch matches closely the pitch in the recordings by Anon Torimi of rails assigned to Rallus indicus. I downloaded Torimi’s recordings from xeno-canto.org. I invite Shanghai birders to do the same. Get to know the sounds of both R. indicus and the extralimital R. aquaticus and start adding these species to your own Shanghai lists.
AMUR FALCON CATCHING GNATS
On Saturday we were amazed to see Amur Falcon catching flies with their talons. We had five near Big Bend (31.000321, 121.938074). In top left of the three-panel photo above, the falcon has spotted its prey and is accelerating toward it. In bottom left, the gnat is visible as the falcon zeroes in. At right, the falcon raises its talons for its tiny prey.
The instinct to use its talons is inefficient in this case and shows that Amur Falcon has evolved to hunt larger game. Smaller aerialists such as swifts, nightjars, swallows, and flycatchers snatch up their prey directly with the mouth.
PREACHING THE GOSPEL OF CONSERVATIONISM
I saw the car with lettering saying “Pudong TV” and waved the journalists over. I told them I had something they might want to hear. Echoing my recent post Save Nanhui, I told the pair that Shanghai can have it all. It can be a world financial hub and China’s greatest metropolis and be a green city. It can follow Hong Kong and Singapore and develop a world-class urban wetland reserve easily accessible to nature lovers without their own car. Nanhui’s old wetland, I said, pointing to the defunct reserve behind us, could be the site of such a reserve.
As I talked, a small crowd gathered. Most seemed supportive of my ideas. I was not surprised. A world-class wetland at Nanhui is a basic conservationist idea, and basic conservationist ideas have broad appeal.
The flycatcher was attracted by mealworms speared by photographers onto a soft steel wire. The wire was hung from a branch, enticing the flycatcher to hover to snatch the bait. The bird was appearing every 10 minutes.
I expressed concern but did not feel the need to be critical or intervene. The photographers obviously liked the flycatcher, did not think that they were harming it, and were enjoying themselves immensely.
I watched the flycatcher attack the mealworms. I think it unlikely that the wire would harm the bird. The bigger problem may be that the free protein will keep the bird here an unnaturally long time. A passage migrant through Earth’s largest city, Narcissus Flycatcher should be in Borneo by now.
INTERESTING WECHAT EXCHANGE ON ARCTIC WARBLER
Shanghai Birding is the WeChat companion to shanghaibirding.com. In it, we exchange real-time reports and engage in discussions about birding in Shanghai and all China.
A discussion on 10 Nov. about Arctic Warbler showed the utility to birders of social media in general and Shanghai Birding in particular. Members Jonathan Martinez (based in Shenzhen) and Paul Holt (based in Beijing) shared their knowledge about Arctic Warbler and its sister species. In so doing, they shed light on the situation, still very imperfectly understood, of the Arctic-type complex in Shanghai.
Holt led off:
Paul Holt (PH): I see from a recent posting that @李伟 photographed an Arctic Warbler at Nanhui on the 28 October. Great images! Isn’t that extremely late? The latest ever Beijing record’s over two weeks earlier than that.
I then posted a long list of my Arctic-type records from autumn 2014 and autumn 2015. In the list, I bunched together all members of the Arctic Warbler Complex (Arctic Warbler Phylloscopus borealis borealis and P. b. kennicotti, Kamchatka Leaf Warbler P. examinandus, and Japanese Leaf Warbler P. xanthodryas). I list all three species because, although it is presumed that the vast majority of spring and autumn records in Shanghai pertain to borealis, it is far from certain what the proportions are. (Arctic Warbler and its sister species are nearly impossible to separate on morphology but are distinguishable by voice.)
The latest autumn record I had of an Arctic-type warbler was 24 Oct. (2015).
Holt wrote back:
PH: Thanks @Craig (大山雀) Unless I’m missing something 28 October is later than any of the records you cite (but just by four days). Could it be that the Nanhui sighting is Shanghai’s latest ever? Also it’s interesting that you mention all three species. Have any of your region’s Arctic-types been identified to a species other than borealis?
Craig Brelsford (CB): @Paul Holt I have not recorded anything other than borealis around Shanghai. (All confirmed borealis records are of individuals singing in spring.) I also suspect that a record of xanthodryas is next to impossible in Shanghai. I am aware that citing all three names is not a perfect solution. I list all three species because I believe information is insufficient. No one knows how many Arctic-type in Shanghai are borealis and how many examinandus. Very basic facts about the species in east-central China are unclear. Maybe someday studies will confirm that an Arctic-type in east-central China is borealis, with a probability of 99%. In that case, I would probably assign any silent Arctic-type I saw to borealis. Do you have any suggestions?
A few minutes later, I added:
CB: Just remembered that Michael Grunwell, Elaine Du, and I had Arctic-type this past Sat. 5 Nov. We got a good look at the bird, too. October was a warm, wet month in Shanghai, and the entire fall migration season seems to be late a week or two. Would others here agree?
PH: I’ve never seen xanthodryas in mainland China, have only ever encountered two examinandus (which were the first records for Liaoning & Hebei. Both sound recorded) here & have too little to go on I’m afraid @Craig (大山雀). Personally I log everything as Arctic Warbler by default, though that’s far from perfect. Until more of us work on this awkward group & make an effort to sound-record them, it’ll be a long time yet before a truer picture of their patterns of occurrence emerges. Cracking late record last weekend @Craig (大山雀). Surely that must be a good candidate for being the latest ever.
CB: @Paul Holt Maybe for simplicity’s sake I should log everything as Arctic. I have hesitated because I dislike speculation, and besides your very reliable records from up north I have little else to go on.
At this Martinez came in with his south-China perspective:
Jonathan Martinez (JM): I’ve heard xanthodryas on Fujian coast in early May and had a bird caught in October at Xitou identified as xanthodryas by DNA on tail feathers among about 15 borealis. I found an examinandus in central Guangxi in September, first suspected by call on a bird wave and clearly identified with call a few days later. I suspect examinandus is not a coastal migrant and probably goes through mainland China. I think still the only species recorded in Hong Kong is borealis, despite many looking for these.
CB: Thanks! With a confirmed xanthodryas in Fujian and examinandus only “suspected” not to use the Chinese coast, I’ll keep my clunky three-species listing. Arctic-type Warbler in China is a subject crying out for more research.
Did you know that the birding area at Nanhui is a cape? This is an aspect of Nanhui that perhaps requires more discussion. The 30-km stretch of coastline is the southeastern-most point of Pudong as well as of the entire city-province of Shanghai.
Cape Nanhui (I like the ring of that) juts out between the mouth of the Yangtze River and Hangzhou Bay. The cape aspect of Nanhui makes it even more valuable to migrating birds than regular coastline. Nanhui is a stepping stone, catching birds that have just made a non-stop crossing of the mouth of the Yangtze River (in fall) or a non-stop crossing of Hangzhou Bay (in spring).
I also find it interesting that one never hears of the “Shanghai Peninsula.” It’s a term with explanatory power. Although rather nubby, the Shanghai Peninsula is clearly a promontory between the mouth of the Yangtze River and Hangzhou Bay. Cape Nanhui is the tip of the promontory.
If conservationists talk about a nature reserve for “Cape Nanhui,” the tip of the “Shanghai Peninsula,” then maybe they will have a stronger case.
A NOTE FROM TOMMY PEDERSEN
Tommy Pedersen is a pilot with Emirates. He is Norwegian and has been based in Dubai for many years. An accomplished birder, Tommy created uaebirding.com. This outstanding site is the best introduction to birding in the United Arab Emirates and the Arabian Peninsula.
Tommy recently sent a message to shanghaibirding.com:
I had a work flight to Shanghai 9-11 November 2016, and following Craig’s excellent site, I decided to visit Nanhui.
I booked a room at Holiday Inn Express (no English spoken, cold and drafty rooms), close to the Magic Parking Lot and Nanhui Nature Reserve. Two targets: Saunders’s Gull and Reed Parrotbill.
On Day 1, 9 November, I was extremely lucky and bumped into Craig and Elaine with Erica, who took me to the nature reserve. We had a jolly good time (at least I was), and Saunders’s Gulls were soon spotted (http://ebird.org/ebird/view/checklist/S32503941).
Gadwall Anas strepera 8
Eurasian Wigeon A. penelope 30
Mallard A. platyrhynchos 8
Eastern Spot-billed Duck A. zonorhyncha 150
Northern Shoveler A. clypeata 2
Tufted Duck Aythya fuligula 1
Common Pheasant Phasianus colchicus 4
Little Grebe Tachybaptus ruficollis 25
Great Cormorant Eurasian Phalacrocorax carbo 40
Eurasian Bittern Botaurus stellaris 1
Grey Heron Ardea cinerea 100
Great Egret A. alba 30
Little Egret Egretta garzetta 60
Eastern Cattle Egret Bubulcus coromandus 1
Black-crowned Night Heron Nycticorax nycticorax 1
Eurasian Spoonbill Platalea leucorodia 17
Black-faced Spoonbill P. minor 15
Eurasian/Black-faced Spoonbill P. leucorodia/minor 30
Brown-cheeked Rail Rallus indicus 2
Water/Brown-cheeked Rail R. aquaticus/indicus 3
White-breasted Waterhen Amaurornis phoenicurus 1
Common Moorhen Gallinula chloropus 3
Eurasian Coot Fulica atra 4
Pied Avocet Recurvirostra avosetta 3
Kentish Plover Charadrius alexandrinus 1
Common Snipe Gallinago gallinago 14
Common Sandpiper Actitis hypoleucos 1
Green Sandpiper Tringa ochropus 2
Spotted Redshank T. erythropus 80
Common Greenshank T. nebularia 5
Feral Pigeon (Rock Dove) Columba livia 1
Oriental Turtle Dove Streptopelia orientalis 3
Spotted Dove S. chinensis 3
Common Kestrel Falco tinnunculus 3
Amur Falcon F. amurensis 1
Peregrine Falcon F. peregrinus 1 Falco sp. 2
Long-tailed Shrike Lanius schach 40
Hair-crested Drongo Dicrurus hottentottus 1
Eurasian/Oriental Skylark Alauda arvensis/gulgula 1 singing
Barn Swallow Hirundo rustica 8
Yellow-bellied Tit Periparus venustulus 4
Chinese Penduline Tit Remiz consobrinus 20
Light-vented Bulbul Pycnonotus sinensis 25
Brown-flanked Bush Warbler Horornis fortipes 1
Pallas’s Leaf Warbler Phylloscopus proregulus 18
Yellow-browed Warbler P. inornatus 4
Black-browed Reed Warbler Acrocephalus bistrigiceps 1
Plain Prinia Prinia inornata 4
Reed Parrotbill Paradoxornis heudei 18
Vinous-throated Parrotbill Sinosuthora webbiana 35
Japanese White-eye Zosterops japonicus 2
Crested Myna Acridotheres cristatellus 10
White’s Thrush Zoothera aurea 7
Japanese Thrush Turdus cardis 5
Eyebrowed Thrush T. obscurus 2
Pale Thrush T. pallidus 6
Dusky Thrush T. eunomus 4
Rufous-tailed Robin Larvivora sibilans 1
Red-flanked Bluetail Tarsiger cyanurus 19
Daurian Redstart Phoenicurus auroreus 18
Stejneger’s Stonechat Saxicola stejnegeri 2
Eurasian Tree Sparrow Passer montanus 150
Eastern Yellow Wagtail Motacilla tschutschensis taivana 8
White Wagtail M. alba 14
Buff-bellied Pipit Anthus rubescens 80
Chestnut-eared Bunting Emberiza fucata 7
Rustic Bunting E. rustica 2
Yellow-throated Bunting E. elegans 3
Yellow-breasted Bunting E. aureola 3
Black-faced Bunting E. spodocephala 14
Pallas’s Reed Bunting E. pallasi 16
List 1 of 1 for Tues. 15 Nov. 2016 (16 species). Zhongshan Park (Zhōngshān Gōngyuán [中山公园]; 31.221888, 121.420066), urban green space in Changning District, Shanghai. Partly cloudy. Low 12° C, high 17° C. Humidity 62%. Visibility 10 km. Wind NE 23 km/h. PM2.5 AQI: 93 (moderate). Sunrise 06:22, sunset 16:55. TUE 15 NOV 2016 13:00-15:00. Craig Brelsford & Elaine Du.
Spotted Dove Streptopelia chinensis 5
Common Kingfisher Alcedo atthis 1
Long-tailed Shrike Lanius schach 2
Japanese Tit Parus minor 2
Light-vented Bulbul Pycnonotus sinensis 30
Pallas’s Leaf Warbler Phylloscopus proregulus 4
Yellow-browed Warbler P. inornatus 1
Chinese Hwamei Garrulax canorus 3
Grey-backed Thrush Turdus hortulorum 1
Chinese Blackbird T. mandarinus 4
Eyebrowed Thrush T. obscurus 3
Oriental Magpie-Robin Copsychus saularis 3
Red-flanked Bluetail Tarsiger cyanurus 4
Narcissus Flycatcher Ficedula narcissina 1
Eurasian Tree Sparrow Passer montanus 20
White Wagtail Motacilla alba leucopsis 2
Editor’s note: 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.
Last Sat. 24 Sept. 2016 at Nanhui, my object of observation was Pale-legged Leaf Warbler, one of the Big 5 Leaf Warblers in the Shanghai region. In both spring and autumn, Phylloscopus tenellipes passes through Earth’s greatest city in considerable numbers, giving Shanghai birders ample opportunity to study it. A lookalike species, Sakhalin Leaf WarblerP. borealoides, also has been noted in Shanghai.
In this post, I shall outline the near-impossibility of distinguishing Pale-legged Leaf Warbler from Sakhalin Leaf Warbler on anything but song, and I will show you some of the traits of “Pale-Sak” that set this species pair apart from other leaf warblers. I also have a roundup of the other birds I noted this past Saturday.
ONLY SONG CAN SAFELY SEPARATE PALE-LEGGED FROM SAKHALIN
Pale-legged Leaf Warbler is safely separable from Sakhalin Leaf Warbler only by song. 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” (1). Mark Brazil says field separation of Pale-Sak is “uncertain,” and he warns readers to “beware light conditions” (2). P. 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” (3). 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.
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 WarblerPhylloscopus proregulus, Yellow-browed WarblerP. inornatus, Arctic WarblerP. borealis, and Eastern Crowned WarblerP. 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 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.
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 WarblerPhylloscopus borealis, Kamchatka Leaf WarblerP. examinandus, and Japanese Leaf WarblerP. 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 WarblerP. fuscatus, an uncommon migrant and winter visitor in Shanghai, and the scarce passage migrant Two-barred WarblerP. plumbeitarsus.
— Pale-legged/Sakhalin Leaf Warbler constantly pumps its tail.
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.
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 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.
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: 19 OCT. 2016
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 written 18 Oct. 2016, 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.”
ROUNDUP FOR SATURDAY 24 SEPT. 2016
Stimulating discussions about leaf warblers enlivened the lulls on a day in which my wife Elaine Du and I once again partnered with veteran British birder Michael Grunwell. We noted 69 species, starting at the sod farm south of Pudong airport then spending the rest of the day at Nanhui. We reunited briefly with the Sino-German birding duo of Xueping and Stephan Popp, and we met Dutch birder Benjamin Muis. Highlights:
Juvenile spotted on mudflats at high tide. A far-northern, trans-Eurasian breeder, Philomachus pugnax is a scarce passage migrant in Shanghai. Amid the greenshanks and godwits, the Ruff stood out with its buff-washed head and scaly upperparts. Juvenile Ruff resembles Buff-breasted Sandpiper, a much smaller American bird that we quickly ruled out.
1 juv. Earlier mis’ID as Peregrine Falcon; corrected 3 Oct. 2016. Thanks to the commenters below for pointing out the error.
A week ago ca. 2500, on Saturday only 10. Coastal birding is a parade of change, especially in migration season.
Other goodies: Eurasian Wryneck 2, Japanese Paradise Flycatcher 6, Amur Paradise Flycatcher 1, Richard’s Pipit 5, White’s Thrush 5 first-of-season, Rufous-tailed Robin 1 first-of-season. We introduced Benjamin to Reed Parrotbill calling unseen from the reeds below, we had a strong count of 16 Blue-and-white Flycatcher, and we noted two endangered species: Far Eastern Curlew and Yellow-breasted Bunting.
Eurasian Wigeon Anas penelope 5
Eurasian Teal A. crecca ca. 300
Common Pheasant Phasianus colchicus 5
Little Grebe Tachybaptus ruficollis 40
Great Crested Grebe Podiceps cristatus 1
Yellow Bittern Ixobrychus sinensis 1
Grey Heron Ardea cinerea 30
Great Egret A. alba 13
Intermediate Egret A. intermedia 2
Little Egret Egretta garzetta 12
Eastern Cattle Egret Bubulcus coromandus 20
Chinese Pond Heron Ardeola bacchus 4
Black-crowned Night Heron Nycticorax nycticorax 10
Common Moorhen Gallinula chloropus 2
Eurasian Coot Fulica atra 8
Black-winged Stilt Himantopus himantopus 5
Pied Avocet Recurvirostra avosetta 5
Grey Plover Pluvialis squatarola 1
Kentish Plover Charadrius alexandrinus 100
Far Eastern Curlew Numenius madagascariensis 1
Black-tailed Godwit Limosa limosa melanuroides 14
Red-necked Stint Calidris ruficollis 20
Dunlin C. alpina 30
Green Sandpiper Tringa ochropus 4
Spotted Redshank T. erythropus 4
Common Greenshank T. nebularia 30
Marsh Sandpiper T. stagnatilis 8
Common Redshank T. totanus 5
Ruff Philomachus pugnax 1
White-winged Tern Chlidonias leucopterus 10
Whiskered Tern C. hybrida 5
Feral Pigeon (Rock Dove) Columba livia 5
Spotted Dove Streptopelia chinensis 6 Cuculus sp. 4
Common Kingfisher Alcedo atthis 1
Eurasian Wryneck Jynx torquilla 2
Eurasian Hobby Falco subbuteo 1 juv.
Black-winged Cuckooshrike Coracina melaschistos 1
Brown Shrike Lanius cristatus 3
Long-tailed Shrike L. schach 28
Black-naped Oriole Oriolus chinensis 1
Black Drongo Dicrurus macrocercus 1
Japanese Paradise Flycatcher Terpsiphone atrocaudata 6
Amur Paradise Flycatcher T. incei 1
Oriental Skylark Alauda gulgula 3
Sand/Pale Martin Riparia riparia/diluta 1
Barn Swallow Hirundo rustica ca. 200
Light-vented Bulbul Pycnonotus sinensis 4
Yellow-browed Warbler Phylloscopus inornatus 1
Pale-legged/Sakhalin Leaf Warbler P. tenellipes/borealoides 10
Eastern Crowned Warbler P. coronatus 5
Zitting Cisticola Cisticola juncidis 1
Plain Prinia Prinia inornata 2
Reed Parrotbill Paradoxornis heudei 1
Crested Myna Acridotheres cristatellus 2
White’s Thrush Zoothera aurea 5
Dark-sided Flycatcher Muscicapa sibirica 1
Asian Brown Flycatcher M. dauurica 8
Blue-and-white Flycatcher Cyanoptila cyanomelana 16
Rufous-tailed Robin Larvivora sibilans 1
Blue Rock Thrush Monticola solitarius philippensis 1
Eurasian Tree Sparrow Passer montanus 100
Eastern Yellow Wagtail Motacilla tschutschensis 4
White Wagtail M. alba 4
Richard’s Pipit Anthus richardi 1
Yellow-breasted Bunting Emberiza aureola 1
(1) Alström, Per. 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.
(3) del Hoyo, Josep, et al., eds. The Handbook of the Birds of the World. Lynx Edicions. Vol. 11, “Old World Flycatchers to Old World Warblers,” species accounts for Pale-legged Leaf Warbler (p. 663) and Sakhalin Leaf Warbler (p. 664) written by P. Clement.