Arctic Warbler???

[Ramon Quisumbing]

ID please. Is this an Arctic Warbler or one of our endemic Leaf-Warblers (I hope)? Taken this morning in the understorey of the forest of Mt. Banahaw at about 2,500 feet elevation.

[paulbourdin]

The first thing to say is this isn't the Philippine endemic Lemon-throated Warbler. There is no hint of yellow on the throat or the vent, and the first photograph appear to show a wing-bar.

That means the bird is of the Arctic Warbler Complex, now split into 3, Arctic Warbler, Japanese Warbler and Kamchatka Warbler. As these changes are relatively new to me I can't be authoritative on this, but from what I read, Japanese and Kamchatka Warblers are somewaht yellower on the flanks than Arctic, and have a broader wing bar (according to Brazil, Birds of East Asia). If anything this bird has even less yellow on the flanks than the vent. They are also said to be greener above (while Arctic is browner)

I've been told there is a difference in the calls, but this will take a while to sort out as none of the published calls I can find differentiate between the three species (everything on Xeno-canto refers to Arctic Warbler only).

I think we'll still be discussing the separation of these three birds for a long while to come. For now I refer to them as "Arctic warbler type"

[Ramon Quisumbing]

Wow, very technical, Paul. Thanks.

I heard from Dion that you're coming to BK today?

[steve pryor]

Paul,
You have it about right. Even Des, and I are not too sure about these things yet. I am still studying the subject. From what I can tell to now, a lot depends on instinct and eye for judging the bill strength. The smaller billed Arctic types in Phils are probably the Arctic post-split. The bigger-billed ones are either the Japanese LW, or the Kamchatka LW. The Kamchatka LW is the one that supposedly has the strongest overall bill. In any case, for however much we study I still expect that the latter two birds will give us a lot of grief.

[paulbourdin]

Nov 19, 2011 21:32:22 GMT steve pryor said:

From what I can tell to now, a lot depends on instinct and eye for judging the bill strength. The smaller billed Arctic types in Phils are probably the Arctic post-split. The bigger-billed ones are either the Japanese LW, or the Kamchatka LW. The Kamchatka LW is the one that supposedly has the strongest overall bill.

Ah, useful. That means taking ventral photographs and comparing them. The vestiges of a plan!

[des]

The book that best discusses these is Identification for Ringers 2: Genus Phylloscopus [Paperback] by Kenneth Williamson which is out-of-print. The songs of the various new split species are clearly different, the calls less so. I have commercial recordings (420birdsongs of Japan) for xanthodryas and what I think is examinandus. Xanthodryas has a buzzing drrt of typically 16 blips spread over 0.1seconds sounding dzzzt. The 16 seem to be slightly paired, ie 8 pairs. examinandus has 5 or so differently structured blips over 0.1 secs so it sounds less buzzy and more chat-like. Veprintsev's Birdsongs of the Soviet Union also has a recording from southern Sakhalin that is similarly slow and chat-like, with 6 blips over 0.12secs sounding drrt. He also has recrordings of what is labelled as borealis from an unknown location that calls with rather a variety of structures. Krister Mild's recordings of borealis show paired sets of rapid blips occurring as 2 peaks so it sounds like one pair of hard buzzes dzi-dzit. Unfortunately getting more details of these recordings, and of eg Geoff Sample's CDs would require rather more time than I have spare at the moment. I strongly suggest that you get a microphone and record the calls. Sound editing software like Raven, Amadeus etc will allow you to see the call structure and may lead to a good ID.

[steve pryor]

Hi Des,
Veprintsev's stuff? Has it ever been digitalized? It seems to be hard to find, and recorded on LP's.

[des]

Steve: It was released on 4 home-made CDs that I bought from them some years ago.
By the way, of my various video cuts of Arctic in the Philippines only has good sound and that seems to match xanthodryas.