China Birding Notes (1 Viewer)

​How does one go about distinguishing a Greater Short-toed ​Lark (Calandrella brachydactyla) ​from a Hume's Short-toed Lark (C. acutirostris)? The attached photos show a single individual, taken 17 July at Dōnggěicuònà Hú in east-central Qinghai. Elev.: 3950 m. Which species of Short-toed Lark are we dealing with here? The ssp. of Greater Short-toed expected in Qinghai, dukhensis, is "dark brown and heavily streaked above" (HBW 9). Hume's Lark, ssp. tibetana (expected in Qinghai), is "paler, greyer, and less prominently streaked on upperparts than nominate, also has less marked head pattern, with supercilium generally less distinct, especially in front of eye, dark loral stripe less obvious (can appear to be absent)" (HBW 9). THANK YOU.

Craig, I would think these are Hume's Larks but would need to check back to my own photos to refresh my memory! Interested in hearing about how you got on in Qinghai at some stage.

cheers, alan

lewis20126 said:

Craig, I would think these are Hume's Larks but would need to check back to my own photos to refresh my memory! Interested in hearing about how you got on in Qinghai at some stage. ...

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Over at China ID Puzzlers, James Eaton also is calling it for Hume's. James instructs us to note the base of bill and the streaking on the head. In the coming weeks, I'll have a full report on Qinghai-Gansu 2014. By tying up loose ends such as Hume's-Greater, birders like you are helping me speed up production of the report!

China's Answer to the Roadrunner

On my recent Qinghai-Gansu Expedition, our team came upon Mongolian Ground Jays in harsh sunlight. Acquiring the high-quality photos that I crave would be tough, but there was something else I could do: I could tell the story of the interesting behavior of this intelligent corvid, China's answer to the Roadrunner. Like that well-known bird of the American Southwest, the Mongolian Ground Jay is highly terrestrial (though it flies well), and it is drawn to roads. Within minutes, my partners and I were seeing one of the things that attract ground jays to the road: roadkill. Roadkill consists not just of dead vertebrates, but also of insects struck by passing cars. Often, the moths and flies fall not far from where the car hit them, making them easy pickings for the ground jays. While observing the resourceful jays, I was also busy snapping shots. Later, I chose four images that are not of high enough quality to stand alone, but that when put together tell the story of a bird that loves to run and that uses its terrestrial instincts to good effect on the highway. Every picture (or set of pictures!) tells a story! With imagination and knowledge of your bird, your seemingly inadequate shots can be put to good use.

Over at China Birding on Facebook, Gordon Ramel and I are having a discussion about the species of leaf warbler he recently photographed. Leaf-warbler enthusiasts: Can you chip in?

Pallas's Leaf Warbler Complex in Dúlóng Valley, Yunnan

Thank you for taking the time to consider a bird that I photographed in June in the Dúlóng Valley, Yunnan. Here's why I'm calling the bird a Lemon-rumped Warbler.

Let's start by setting forth two principles: (1) One of the chief characteristics of the Pallas's Leaf Warbler complex is a well-defined yellow coronal stripe that is equally distinct throughout its length. (2) Within the Pallas's Leaf Warbler complex, four taxa often show an eye-stripe hooking downward at the rear. Of those four taxa, three are in what I'm calling the "Lemon-rumped Warbler subcomplex": They are the two ssp. in Lemon-rumped Warbler (Phylloscopus chloronotus chloronotus and P. c. simlaensis) plus Sichuan Leaf Warbler (P. forresti, formerly described as P. c. forresti). The other leaf warbler with a downward-hooking eye-stripe is Gansu Leaf Warbler (P. kansuensis).

Note the photos of the bird that I'm calling P. c. chloronotus. Panel 2 (reading clockwise from top left) clearly places this individual within the Pallas's Leaf Warbler complex (bold coronal stripe). Panel 3, moreover, places the bird within that group of four taxa characterized by downward-hooking eye-stripes. From those four taxa, I'll immediately eliminate P. kansuensis and P. c. simlaensis, the latter on the basis of geography and plumage (P. c. simlaensis breeds no farther E than Nepal and is known for being brighter and more boldly marked than the individual here), the former on the basis of geography alone (a bit risky, I know, but P. kansuensis is known to breed only in a compact range far to the N). I'm furthermore going to eliminate P. forresti because it is described as having slightly brighter and more clearly defined plumage markings than P. c. chloronotus, and my impression of the bird pictured here is that it was a "dull" type of Pallas's complex warbler. For comparison, please see the accompanying photos of the Sichuan Leaf Warbler, taken 15 days before I took the photos of the Lemon-rumped Warbler (i.e., both birds presumably are showing worn spring plumage). I think the Sichuan Leaf Warbler has slightly better defined plumage than the bird I'm calling a Lemon-rumped Warbler. Please note that I cannot eliminate P. forresti on the basis of geography, as both P. forresti and P. c. chloronotus are described as occurring in E Tibet, and the Dúlóng Valley borders E Tibet. Breeding elevation and habitat choice are also broadly similar for both P. c. chloronotus and P. forresti. I wish I had more photos, but the ones shown here are the best I got. I also have no recordings of the Lemon-rumped pictured here. Note that even though the voices of P. c. chloronotus and P. forresti are very similar, a clear recording probably would have shown discernible differences. What's your opinion? Am I justified in calling the leaf warbler I photographed at Dúlóng a Lemon-rumped Warbler?

thrush said:

... Every picture (or set of pictures!) tells a story! With imagination and knowledge of your bird, your seemingly inadequate shots can be put to good use.

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Thanks for sharing the interesting story of these birds and the comparison with the road runner (though I suppose these jays generally take smaller prey than the RR).

Gretchen said:

Thanks for sharing the interesting story of these birds and the comparison with the road runner (though I suppose these jays generally take smaller prey than the RR).

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You bet, Gretchen! And welcome back to China.

Hi Craig,

On your Lemon-rumped Warblers (or Pale-rumped Warblers as Clements/Cornell would have them), your photos do look persuasive. However the distribution maps on xeno-canto and birdlife don't show chloronotus occurring, which is puzzling. Too many splits/name changes maybe?!

Jon Gallagher said:

Hi Craig,

On your Lemon-rumped Warblers (or Pale-rumped Warblers as Clements/Cornell would have them), your photos do look persuasive. However the distribution maps on xeno-canto and birdlife don't show chloronotus occurring, which is puzzling. Too many splits/name changes maybe?!

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Hey Jon,

We saw our Lemon-rumped Warblers in the Dulong Valley, in the extreme NW of Yunnan, bordering Burma and the extreme SE corner of Tibet. According to my research, two members of the Pallas's Leaf Warbler complex can be expected in E Tibet and NW Yunnan: Phyllocopus chloronotus chloronotus and P. forresti. My good friend Daniel Bengtsson, writing on Facebook, says that he was seeing P. c. chloronotus in Arunachal Pradesh, very close to the Dulong Valley (the two regions are separated only by the tapered N tip of Burma). It's not surprising that P. c. chloronotus should be in Dulong.

I don't know how accurate the xeno-canto maps are; I remember that our team found Manipur Fulvetta in the Dulong Valley and later checked xeno-canto. The xeno-canto map had the Dulong Valley well out of the range of Manipur Fulvetta.

Take care,

Craig

Do you have only an average camera and worry that you'll never be able to take compelling bird photos? Worry no more! Focus on capturing exciting action. Let your photos show behavior. Let your pictures tell a story! You don't need the most expensive camera to tell a story. Here's a Large-billed Leaf Warbler (乌嘴柳莺, wūzuǐ liǔyīng, Phylloscopus magnirostris). The rain had just stopped at Éméishān (峨眉山), Sichuan on 10 June 2014. Nikon D3S, 600 mm, F/5.6. My expensive camera happens to be able to take useful shots of this tiny, strongly backlit leaf warbler 30 m away. Your setup may allow you to do more or less than what I've managed to do here. No matter; the point is that one shouldn't give up too early. Shoot first and worry about quality later--especially when your bird is showing interesting behavior!

Ready to Read: "Sichuan & Yunnan, June 2014"

In June 2014, I became one of the first birders to visit the Dúlóng Valley, "The Last Green Valley in China," in far NW Yunnan. In addition to the Dulong Valley, my team visited the Old Erlang Road and Éméishān in Sichuan. I have completed the text-only version of the report. To view it, please visit the Index to Craig's Reports on craigbrelsford.com. The report is called "Sichuan & Yunnan, June 2014" and is at the top of the list. (To go directly to the report, click here.)

Summary

The trip got off to a good start at Old Erlang Road. At Lóngcānggōu, within the space of 12 hours, we were caught in a power surge that destroyed $600 worth of my equipment and hit a bump that destroyed the oil pan on our rented Chevy Captiva. Constant rain also inhibited us. Nonetheless, it being breeding season meant that when the weather was good, birds were out in numbers. After visiting Éméishān, we drove non-stop to NW Yunnan and the remote Dúlóng Valley.

Highlights

-- In collaboration with Per Alström, finding, photographing, and sound-recording Plain-backed Thrushes at the dramatic Salween-Irrawaddy Divide in the Gāolígòng Mountains

-- In the Dúlóng Valley, finding several species of bird with limited ranges in China, among them Black-eared Shrike-babbler, Lemon-rumped Warbler, Yellow-throated Fulvetta, Scaly Laughingthrush, Rusty-fronted Barwing, Streak-throated Barwing, Beautiful Sibia, Rusty-flanked Treecreeper, Yellow-bellied Flowerpecker, Fire-tailed Sunbird, and Scarlet Finch

-- On the Old Erlang Road, spotting, waiting out, and photographing a rare female Firethroat, as well as photographing and sound-recording a male

-- Finding and photographing a pair of Fire-tailed Myzornis at the Salween-Irrawaddy Divide

-- In total, noting 193 species of bird, representing 12 orders and 45 families (systematic list at bottom of report)

Please enjoy the report and reach me with any questions or comments.

Sulphur-bellied Warbler, Qilian Mtns., Gansu

Last month, I sent out photos of a Phylloscopus and asked for your opinion. I now have a conclusive and possibly surprising ID of those birds. In the attached four-panel photo, the birds in panels 1-3 are Sulphur-bellied Warblers (灰柳莺, huī liǔyīng, Phylloscopus griseolus). Below, I offer some of the evidence supporting my ID of these birds as Sulphur-bellied Warblers and not Alpine Leaf Warblers (华西柳莺, huáxī liǔyīng, Phylloscopus occisinensis):

1. Habitat

The birds in panels 1-3 were photographed 24 July ​in the Qilian Mtns. near Sùběi in W Gansu. Elev.: 2520 m. I was traveling with Brian Ivon Jones and Jan-Erik Nilsén. We found these birds in a sparsely vegetated desert ravine. There was no running water anywhere near the site. I've never seen Alpines in habitat quite like the barren place where we encountered our birds. I've seen Alpines only in dwarf juniper and rhododendron habitat. Sulphur-bellieds, by contrast, are well-known for their preference for "stony, bushy slopes" (Birds of India).

2. Behavior

We watched our Sulphur-bellieds for a solid 5 mins. The birds were on the ground the entire time. I'd never seen such a ground-loving leaf warbler. Watching them, I had the immediate impression that I wasn't seeing a typical leaf warbler at all. Although I've seen Alpines on the ground, they are much more likely to be encountered in vegetation. In HBW 11, the VERY FIRST characteristic the authors use to discriminate between Sulphur-bellied and Tickell's/Alpine is the former's "ground-loving habits."

3. Plumage characters

The birds in panels 1-3 (a) are colder above than Alpines, lacking olive hues; (b) show supercilia that are brighter than the throat, unlike Alpines, whose supercilia are similar in coloration to the throat; (c) show greyish-white (Sulphur-bellied), not greenish-olive (Alpine), edges to the remiges. (​​See four-panel photo for more distinctions.)​

The birds are clearly Sulphur-bellieds. In light of this discovery, what lessons can you and I draw?

1. Experts aren't infallible.

Not a single birder to whom I originally circulated these photos thought that they showed Sulphur-bellied Warblers. Almost all said Alpine Leaf Warbler. None mentioned Sulphur-bellied. Even if the birds I photographed had turned out to be Alpines, not mentioning even the possibility of the superficially very similar Sulphur-bellied is ITSELF an oversight. Though usually reliable, even experts make mistakes.​

2. Never stop investigating.

On our July trip to Qinghai and Gansu, Brian kept insisting that the places we were visiting had been little birded and that we should therefore throw many of our assumptions out the window. Few or no experts have a clear idea of what birds are to be expected in the Qilian Mountains, one of the most remote mountain ranges on Earth. With that idea in mind, I kept investigating our Sulphur-bellieds, even after the experts had given their opinion.

3. My work on Phylloscopus is paying off--and yours can, too!​

To make myself a better birder and to write better text for my photo field guide to the birds of China, I've made Phylloscopus ​a pet project. Slowly, the fog is clearing and I'm getting a strong grasp of this tough genus. With hard work, it IS possible to get better at ID-ing leaf warblers!

Hi Craig - your photographed birds seem freshly out of the nest and probably still showing signs of Juv plumage - did you happen to see and photograph the parents or any adult birds at that site - and have you compared your pics to those of newly fledged Alpine????

Compare your birds to this - http://orientalbirdimages.org/search.php?Bird_ID=2885&Bird_Image_ID=15346&p=6

As for habitat, and lower than normal elevation for Alpine,you also have to include juv Buff-throated Warbler in your ID calculations.

china guy said:

Hi Craig - your photographed birds seem freshly out of the nest and probably still showing signs of Juv plumage - did you happen to see and photograph the parents or any adult birds at that site - and have you compared your pics to those of newly fledged Alpine????

Compare your birds to this - http://orientalbirdimages.org/search.php?Bird_ID=2885&Bird_Image_ID=15346&p=6

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Hi Sid, nice to see you checking in here. I've been putting up good content on this thread for a long while, and will continue to do so; it'd be good to continue getting input from you.

Have you seen a great many Sulphur-bellied Warblers in your life, Sid? For if you have, then you'd have been immediately struck by their accentor-like, ground-loving behavior. Their preferred habitat is distinctive also: Sulphur-bellieds are more high-country desert breeders, not high-country scrub breeders, as is more typically the case with Alpine Leaf Warblers.

My photos show only young birds, but my ID is based not only on plumage characters but also the deeply "terrestrial" impression that these birds gave me. Please note closely what I wrote above: "We watched our Sulphur-bellieds for a solid 5 mins. The birds were on the ground the entire time. I'd never seen such a ground-loving leaf warbler. ... In HBW 11, the VERY FIRST characteristic the authors use to discriminate between Sulphur-bellied and Tickell's/Alpine is the former's 'ground-loving habits.'"

In addition to the ground-loving behavior of the birds I photographed, consider the habitat: rocky and hilly, with sparse, low vegetation--very much what one would expect for P. griseolus (Sulphur-bellied), less what one would expect for P. occisinensis (Alpine).

Note next our location: Qilian Mtns. in W Gansu, a place where (according to HBW 11) P. griselous is expected ("Qilian Mtns." get an explicit mention in the range description of P. griseolus), and where P. occisinensis ("E Qinghai, C Gansu") and P. subaffinis (Buff-throated Warbler, "SE Qinghai") would be more of a surprise. Note also that Dusky Warbler (P. fuscatus robustus) and Smoky Warbler (P. fuligventer weigoldi) are not expected in far W Gansu and in any case are less likely to be found on a rocky desert hillside with low, sparse vegetation.

My partners and I were in highly unusual leaf-warbler territory: a rock-studded desert ravine. This territory must have been close to where my birds bred, for, as you noted, the birds I photographed seem to have just left the nest. What is the one leaf warbler most associated with such a habitat? Sulphur-bellied Warbler.

If the birds I photographed are not P. griseolus, then what are they? Alpines (the choice of my correspondents)? Well, note this: a week or so before we were in W Gansu, my partners and I saw P. occisinensis at the tail end of breeding season near Qinghai Lake. Where were our P. occisinensis? They were in their breeding habitat of dwarf juniper and rhododendron. Also, in 2013, I saw Alpines at the end of July, still in their breeding habitat and still very much responsive to playback. Likewise, the Alpines we saw near Qinghai Lake this year were very responsive to playback. All the Alpines I've seen in late July have been very much in breeding and territorial mode and very much in their breeding habitat.

Our birds in W Gansu were Alpines? Then why were they in a place so much unlike the typical breeding habitat of P. occisinensis, at a time of year when P. occisinensis is still more in breeding mode than in migration mode?

It would have been nice to have photographed the adult as well as achieved a clear recording of the voice, but let's not belabor the issue. They're not Alpines. They're P. griseolus.

Hi Craig - weak flying Juvenile birds, in their attempts to keep out of the claws and talons of predators may often show terrestrial behavior thats not normally associated with adults. As for an ID on your birds I'd actually swing towards Buff-throated over Alpine - but with many juvenile LBJ's, especially leaf-warblers, making a certain call without seeing and preferably hearing adults - is always a difficult job.

Hi Craig,

Thank you for the frank and honest discussion regarding the confusion over and difficulty of species identification. Yours, along with several recent admissions by some of the top US birders, make me realize that there is no shame in my being unable to ID an unknown (sometimes even known) bird down to the species level (In China I sometimes consider myself lucky to get to Genus! . Just this morning, here in California, I spotted a Sharp-shinned hawk as it flew into a nearby tree. I had several minutes to observe it and it helpfully flicked its tail and moved about on the limb several times offering up good views of the field marks. However, not once was the entire bird visible due to my position and intervening foliage, and its flight in to perch, ducking and weaving between the branches, gave me only a quick look of its wing/head profile. So, was my ID correct? Or, was it really just a smallish Coopers?.. It makes me feel a lot better knowing that even you experts struggle with some ID's.

Of course, matching a seen bird to a currently defined species (one with a binomial name) is only one piece of the puzzle. The elephant in the room is just how do we determine a species? I recently read two articles that discussed the concept of species that you might find interesting.

This first article talks about the 26 published concepts of species and how there may(?) be a way to unify them into a single concept:
http://www.google.com/url?sa=t&rct=...Vg0ZDvn7tIOPQ4MQ28A976w&bvm=bv.74115972,d.aWw

This second article is a monograph by a guy who wrote "Handbook of Avian Hybrids of the World, 2006". The first chapter "On Species" is thought provoking:
http://www.google.com/url?sa=t&rct=...1zoVqKdA0IuTd0Q&bvm=bv.74115972,d.aWw&cad=rja

Thank you again, especially for the great job you are doing to bring Chinese birding to the forefront and helping the rest of us mere mortals improve our ID'ing skills. I hope to remember some of your ID tips and hints as I wander around Shanghai again on my vacation, just a few short weeks from now.

Bruce

Just to add a bit to the discussion, I've found occinensis in North Western Hunan at Hu Ping Shan at elevation around 1500 to 1700 meters, the birds were found there always associated with recently abandonned cultivated field and were most often seen in the grass very close to ground level looking for prey. Subaffinis can also be found there in the highest elevation around 2000 meters in shrubby area.
Just to said that occinensis to me needs open grassy area to breed...

I also would be very cautious on ID phyllosc based on juvenil plumage and without any vocalisations recorded. I guess that pics of adults would have help to clinch the ID...
I have a single example also from Hu Ping Shan, I was watching at a phyllosc for wich i was pretty convinced was a goodsoni until I saw an adult ricketti fed him....

All the best,

Jonathan

china guy said:

Hi Craig - weak flying Juvenile birds, in their attempts to keep out of the claws and talons of predators may often show terrestrial behavior thats not normally associated with adults. As for an ID on your birds I'd actually swing towards Buff-throated over Alpine - but with many juvenile LBJ's, especially leaf-warblers, making a certain call without seeing and preferably hearing adults - is always a difficult job.

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You're disappointing me, Sid. Although you didn't actually witness the birds as I did, my ID is based not only on direct evidence but very much also on circumstantial evidence, logic, and the literature. You have just as much access to the literature as I, and as a longtime birder, you must use circumstantial evidence and logic to achieve your IDs.

I know how to ID birds and know when to limit my listing to "Phylloscopus sp." However, in this case, having studied the literature, examined the circumstantial evidence, and applied logic, I can (and you should) confidently "lock in" on Sulphur-bellied Warbler P. griseolus.

My prime piece of literature in this case is HBW 11, probably the best reference in existence for the 44 species of leaf warbler in China. Having relied on HBW 11 extensively to write my draft of Phylloscopus, I have come to know it, trust it, and admire it. HBW 11 may be inaccurate or incomplete in some areas, and, as I said before, in the Qilian Mountains and W Gansu, birders have been few. But let's assume that the species accounts in HBW are by and large accurate.

HBW 11 has Tickell's Leaf Warbler (Alpine Leaf Warbler P. occisinensis hadn't been split off yet) occurring no farther W than "E Qinghai and C Gansu," an area about 1000 km E of the spot in W Gansu where my partners and I saw the Sulphur-bellieds. I'd like to know, Sid, what you and I are supposed to do with that information. Shall we say that HBW 11 is wrong and that the range stretches 1000 km farther W than the authors assume? HBW could be wrong here, but it probably isn't--again, taking into consideration the overall high quality and accuracy of its treatment of Phylloscopus as a whole.

As for Buff-throated Warbler P. subaffinis, HBW 11 has the range extending to "SE Qinghai"--1500-2000 km from our spot in W Gansu!

For P. griseolus, HBW 11 has W Gansu smack in the heart of its range--and even mentions the "Qilian Mountains" in its range description. (Among the leaf warblers under consideration, only for P. griseolus are the very remote and little-known Qilian Mtns. mentioned.)

We therefore can say that, according to HBW 11 and other sources, among the handful of lookalike leaf warblers we've been considering, the one species most to be expected at our spot in W Gansu is none other than Sulphur-bellied Warbler P. griseolus.

That's pretty strong evidence, but there's even stronger: habitat. In bird books, range descriptions have a greater chance of inaccuracy than habitat descriptions, as range descriptions rely heavily on birders and scientists actually making records--something of which there are too few in China. Habitat descriptions, however, are based on long study of birds, usually by experts. Ergo, if HBW 11 is reasonably accurate in its range descriptions of leaf warblers, then we can expect it to be even more reliable in its descriptions of habitat.

In the case of the birds my partners and I saw in W Gansu, it is unanimously agreed that 2 of the 3 birds were juveniles that had only recently left the nest. When you see a family of birds with juveniles that just left the nest, the family might as well be crying out, "Dude, this is where we bred! This is where our babies were born! This is our breeding habitat!" Now, what kind of breeding habitat was that? For leaf warblers, it's very unusual habitat, habitat very much unlike the habitat favored by P. occisinensis, P. subaffinis, and just about any leaf warbler--with the exception of the desert specialist, P. griseolus.

Read what HBW 11 has to say about the breeding habitat of P. griseolus: " ... dry stony mountain slopes, rocky screes and boulder-strewn hillsides with low vegetation ... " That's an admirably accurate description of the steep-sided ravine where my partners and I found those leaf warblers. Consider the description for Tickell's/Alpine: "Breeds among rocks and low bushes in dry barren mountains, alpine and subalpine willows, dwarf juniper, dwarf bamboo and Berberis scrub, also rhododendrons, edges of forest and cultivation ... " That's also a very accurate description (I've seen P. occisinensis in just that type of habitat)--but one of a habitat very much unlike the habitat in which we found our Sulphur-bellieds.

So, to sum up: We have the world's most reliable book on Phylloscopus in China telling us that in the Qilian Mtns. in W Gansu the species of brownish, nondescript, yellow-superciliumed leaf warbler most to be expected is P. griseolus, and we have a record and photos by three experienced birders showing a family of leaf warblers in just the sort of highly distinctive desert habitat favored by P. griseolus for breeding. And I'm still supposed to accept that the birds we saw were Alpines (or even less plausibly, Buff-throateds)? Are you kidding me?

Sure, any juvenile Phylloscopus may spend time on the ground (but not all its time; and our adult too was very much at home hopping and flitting from boulder to boulder); sure, I'd have liked to have heard and recorded a call; sure, I'd like a little stronger sulfur-yellow at the base of the supercilium in my birds; sure, juvenile leaf warblers among the handful of species being considered here can look alike, and yes, there is a photo on OBC of an Alpine juvenile that has brownish ear coverts.

On the other hand, you have birds most closely fitting the description of P. griseolus in the range and habitat in which it is far and away the species most to be expected, and exhibiting the rock-hopping, ground-loving behavior that is its hallmark.

My case may be circumstantial, but it's strong enough to convict. I am certain, and you should be too, that the birds I found in W Gansu are guilty of being Sulphur-bellied Warblers.

jonathmartinez said:

Just to add a bit to the discussion, ...

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Good to hear from you, Jonathan. Normally, having had the chance to observe only juveniles, I wouldn't go beyond "Phylloscopus sp." and a brief speculation about what the species may be. In the case we've been discussing, however, the most appropriate step, it seems to me, is to conclude that the birds are Sulphur-bellied Warblers.

For my reasoning, please take another look at my post in Pane 359. I'm interested in your take.

My partner Jan-Erik Nilsén remembers the vocalizations our W Gansu leaf warblers were making; I don't, probably because I was too busy scrambling around, trying to get photos of our birds.

In any case, even without vocalizations to guide me, I still have another "breeding season clue": habitat. A parent in late breeding season (we saw our birds on 25 July) leading two fledglings around is very likely in its breeding habitat. The steep, boulder-studded desert slopes are very unusual breeding habitat for most leaf warblers, but highly typical of Sulphur-bellied Warblers. Factor in also that a leading reference places the breeding range of Sulphur-bellied smack in the Qilian Mountains and places the breeding ranges of its lookalike congeners at places far distant, and a preponderance of evidence emerges.