Alström’s Warbler & Grey-crowned Warbler at Cape Nanhui, Shanghai

Per's PDF
Some of the more challenging golden spectacled warblers, one of them (bottom L) being Grey Crowned Warbler Seicercus tephrocephalus, seen 14 May at Shanghai’s Cape Nanhui. This graphic was created by Per Alström. The PDF is downloadable through shanghaibirding.com.

by Craig Brelsford
Founder, shanghaibirding.com

Seen Sunday 14 May at Shanghai’s Cape Nanhui: singing Grey-crowned Warbler Seicercus tephrocephalus, and Alström’s Warbler S. soror. Neither species breeds in the region; both are very rare vagrants to Shanghai.

Here is an edited transcript of a recent conversation about these Seicercus warblers at Cape Nanhui. The conversation took place on the WeChat group I founded, Shanghai Birding:

Join Shanghai Birding for the very latest bird sightings in Shanghai.
Join Shanghai Birding for the very latest bird sightings in Shanghai.

Paul Holt: Can you post your recording of yesterday’s [14 May] Alström’s Warbler as well please, Craig?

Craig Brelsford: Will post after I get home. Meanwhile, have you assessed the recording I posted yesterday morning? Do you agree it’s Grey-crowned Warbler? Jonathan Martinez, I’d like your view, too!

Craig Brelsford had earlier posted these sound recordings:

Grey-crowned Warbler Seicercus tephrocephalus 1/3, 14 May, Magic Parking Lot (30.884898, 121.968229), Cape Nanhui (00:36; 3 MB)

Grey-crowned Warbler 2/3 (00:49; 3.6 MB)

Grey-crowned Warbler 3/3 (01:08; 4.3 MB)

PH: Yes, Grey-crowned Warbler!

PH: For what it’s worth, while there are probably 30+ records of “golden-spectacled warblers” from coastal Hebei, very, very few have been as well documented as Craig’s and team’s recent Grey-crowned. Many have been photographed but far fewer sound-recorded. Alström’s is so far the only one so far known to breed north of the Qinling Shan (it’s a scarce and very local breeder at two, possibly three, sites in Beijing). Personally I’ve never seen soror in coastal Hebei (nor am I aware of any being sound-recorded there), but I have noted (and sound-recorded) 2 Bianchi’s S. valentini and 1 Martens’s S. omeiensis in coastal Hebei. I understand that the only (?) three coastal Hebei birds that have been captured and had their DNA compared have all been omeiensis. We’re very, very far from ascertaining the true statuses of these Seicercus in our area, but you perhaps should/might see more in Shanghai and coastal Zhejiang. As many of you already know, there are some excellent sound recordings of these on Per’s site.

CB: Great analysis, Paul, and great that you point out the resources on Per’s site. Jan-Erik and I got good sound recordings of the purported soror yesterday, and Charles Wu and I got some good shots, among them images of the outer tail feathers, which definitely had some white in them.

CB: Grey-crowned Warbler appeared in the microforests almost exactly a year ago: https://www.shanghaibirding.com/grey-crowned-warbler/

PH: Excellent, Craig. As you know they’ve all got white in their outer tails. Alström’s (aka Plain-tailed) doesn’t have much …

Alstrom's Warbler
Alström’s Warbler with splayed tail feathers. (Craig Brelsford)

CB: Right, Paul; thanks. The discussion yesterday was one of comparison and degree. How little must the white be in the tail, we were asking ourselves, for a Seicercus to “qualify” as Alström’s/Plain-tailed? Was the white in our photos a little or a lot? We ended up thinking a little, and that and the song we recorded led us to a determination of soror. I’ll post my photos and recordings as soon as I’m home.

PH: Personally, Craig, I find it very difficult to judge the amount and distribution of white on the tails of these Seicercus in the field and think that a good photo with the tail splayed would really be necessary. Even then, the differences are small and subtle. Tricky group!

Jonathan Martinez: Regarding the ID of these Seicercus, I have found that call is by far the easiest way to ID them. They all have a characteristic call. Some of them, like Alström’s or Bianchi’s, are usually quite vocal; others not as much. It requires much more experience or use of sonogram to ID them by song, but a few of them (Alström’s especially) include their call in their song, and some of them (Grey-crowned, Martens’s) include a trill in their song. Others do not (Alström, Bianchi’s). ID-ing them on plumage is, of course, a level up.

Alstrom's Warbler
Alström’s Warbler Seicercus soror, Microforest 2 (30.926013, 121.970705), 14 May. (Craig Brelsford)

Here is the voice of the Alström’s Warbler that I recorded with my Olympus DM-650 pocket recorder:

Alström’s Warbler Seicercus soror 1/4, 14 May, Microforest 2 (30.926013, 121.970705), Cape Nanhui (00:50; 3.6 MB)

Alström’s Warbler 2/4 (00:08; 1.9 MB)

Alström’s Warbler 3/4 (01:08; 4.3 MB)

Alström’s Warbler 4/4 (00:41; 3.2 MB)

Reach us: info@shanghaibirding.com

Be notified every time we post. Send an
email with “Subscribe” as the subject to
info@shanghaibirding.com

Donate to Shanghai Birding!




Grey-crowned Warbler at Cape Nanhui, First Record for Shanghai

Grey-crowned Warbler
Grey-crowned Warbler, Cape Nanhui, 17 May. First record for Shanghai. (Craig Brelsford)

On the spectacular morning of 17 May at Cape Nanhui, the birding hotspot in Pudong, Kai Pflug and I achieved Shanghai’s first record of Grey-crowned Warbler Seicercus tephrocephalus.

The bird was singing, an amazing incongruity, the bright, sharp south-Chinese Seicercus sound in a tiny wood on the muddy Chinese coast. The golden warbler alighted on a branch for several seconds.

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 as close to Shanghai as Hubei. It is very similar in plumage and song to Martens’s Warbler S. omeiensis but unlike Martens’s has the eye-ring broken at rear. S. tephrocephalus is common to abundant in its normal range of south China and Southeast Asia, but it had never been recorded in Shanghai. The lack of records is probably owing not only to its scarcity but also to its difficulty in identification, particularly for birders unfamiliar with HBW 11.

report
One of the pages dedicated to Seicercus warblers. Taken from a well-known PDF by Per Alström. The PDF is downloadable through shanghaibirding.com either as a PDF or as jpegs contained in a zip folder for easy syncing to your smartphone.

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.

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

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

Grey-crowned Warbler 2/2 (00:23; 1.7 MB)

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

“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]).”

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.

Reach us: info@shanghaibirding.com

Be notified every time we post. Send an
email with “Subscribe” as the subject to
info@shanghaibirding.com

Donate to Shanghai Birding!