fatchun

On 18th Feb 2013 TPK morning
I finally got the photos from my friend.

This is a suspected Seicercus omeiensis for me. At first, I heard a new bird call for me. That was a deep, unmusical call, like "teek teek teek". The call was quite distinctive for me and the warbler was keep calling.
Obviously, the warbler didnt have any wing bar and the eye-ring was completed. Could anyone give any suggestion? All are welcome, thank you so much!

Chun

brendank

A good find! Did you compare the sounds on xeno-canto? Geoff Carey also has an excellent recording of Martens's Warbler here:

http://www.hkbws.org.hk/BBS/redi ... 2&goto=lastpost

A think the lack of an wingbar and thin complete eyering suggests Martens's Warbler.

[ Last edited by brendank at 25/02/2013 22:32 ]

fatchun

Brendan, i have compared all sound of possible Seicercis warbler in HK from  Xeno Canto, i found that only Martens's warbler would call with deep voice. Other Seicercus warblers woulf rather call with high pitch or musically.  Why I coild locate this bird was aboiy its call. A deep "teek teek" sound like what is on Xeno-canto.

fatchun

Could anyone give more advice on this bird?
Thank you so much!

lchunfai

Chun, do you have any recording? I think it is only safe to separate valentini and omeiensis by its call in field. You can compare the recording made by Geoff. (the one in Aberdeen called exactly the same with the one in Pak Sha O and it did response when playing the song)
Or you can take a look of the following:
Phylloscopus & Seicercus by Dr. Per Alström

fatchun

I dont have any voice record. But both warblers of this individual and the one in PSO produced the same distinctive call.

lchunfai

If you think it is, then it is. ^^"

brendank

Alström & Olsson, 1999, suggest that Bianchi's Warbler completely lacks a wingbar in <10% of birds. This bird clearly lacks a wingbar, as did the bird at Aberdeen Reservoir and also the one I saw at LFS in January. The bird at Pak Sha O also seemed to lake a wingbar during my brief views of it. The probability of observing four such Bianchi's Warbler without a wingbar is 0.01% assuming only 10% lack a wingbar suggesting that at least some aren't Bianchi's Warbler.

fatchun

Yes, I think the feature of lacking wing-bar could be a good indicator for sorting out Bianchi's warbler.

lchunfai

Confusion by angle, Too many variations and I am inexperienced, I would not say it is definitely not a Bianchi's because of lacking a wingbar.

http://orientalbirdimages.org/se ... _ID=&pagesize=1

http://orientalbirdimages.org/se ... _ID=&pagesize=1

http://orientalbirdimages.org/se ... _ID=&pagesize=1

Similar case in Plain-tailed Warbler Seicercus soror , nearly invisible wingbar is one of the features, but I don't think I can safely identify by checking the presence of wingbar.

http://orientalbirdimages.org/se ... _ID=&pagesize=1

http://orientalbirdimages.org/se ... _ID=&pagesize=1

http://orientalbirdimages.org/se ... _ID=&pagesize=1  (wingbar?)

http://orientalbirdimages.org/se ... _ID=&pagesize=1  (no wingbar?)

Of Course, the above links may be incorrectly labelled.

It is not surprised to have more than one omeiensis this winter, as we may overlook this species over the years. Lastly, I wanna raise a question, can this bird be a plain-tailed? It doesn't have wingbar and the photos cannot show the forehead, tail, or other characteristic clearly and if it did not call at all.

lchunfai

Sometimes, it cannot tell whether the bird has a wingbar or not by just a brief view or a record photo.

Again, what do you think about these, the two are different individuals.

wgeoff

Don't forget, if you carry a smartphone when birding, these can make acceptable recordings of bird calls.
I use IPhone4 now for my bird recordings. You can clean the recordings afterwards using software and obtain reasonable sonograms.

ajohn

Quote:

Original posted by brendank at 1/03/2013 23:46
Alström & Olsson, 1999, suggest that Bianchi's Warbler completely lacks a wingbar in <10% of birds. This bird clearly lacks a wingbar, as did the bird at Aberdeen Reservoir and also the one I saw at LFS in January. The bird at Pak Sha O also seemed to lake a wingbar during my brief views of it. The probability of observing four such Bianchi's Warbler without a wingbar is 0.01% assuming only 10% lack a wingbar suggesting that at least some aren't Bianchi's Warbler  

But the combined probability cannot be applied to any single individual - the probability for each individual Bianchi's lacking a wing bar remains 10%, regardless of whether other birds seen in the same area also lack a wing bar. Thus for assessing each individual, this feature cannot be used as 'proof' that the bird is not Bianchi's. In fact, it is plausible that the probability changes across the range of the species, and/or is affected by the age of the bird or wear of the feather. Thus for example a fresh-plumaged Bianchi's in Sichuan may have a 10% chance of lacking a wing bar, but a late winter Bianchi's in Hong Kong may have a higher or lower chance (do we know?). Two-barred Warbler has two clear wing bars in the autumn, but these can fade to almost nothing by the following spring (at least, this appears to have happened on the bird that overwintered at Mai Po last year).

I saw a Bianchi's earlier this winter (December) which more or less completely lacked a wing bar. Fortunately it was calling, and the call matched those recordings of Bianchi's on Xeno-canto, and did not match recordings of Martens'. As others have said, the call may be crucial in ID of these species.

[ Last edited by ajohn at 2/03/2013 08:59 ]

fatchun

Quote:

Original posted by ajohn at 2/03/2013 08:57


But the combined probability cannot be applied to any single individual - the probability for each individual Bianchi's lacking a wing bar remains 10%, regardless of whether other birds seen in the  ...

Thank you so much! This information is very useful for thinking boarder when ID-ing a Seisercus warbler. And I agree that the recording is very crucial in ID of these warblers.