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Yellowish-bellied Bush Warbler?

At about 10.15am on Wednesday morning, I was coming down from the Upper School on Po Toi through the gravesites when I was attracted by a bird calling from a thick area of grass and weeds. I was with the bird for the next 5 minutes, although most of the time I could not see it as it remained deep in the scrub. I knew where it was because it was calling continuously. I did manage to get some views and these 4 photographs before it flew off towards some bamboo and woods on the other side of the valley. I did not see it again.

[img]http://www.geoffwelch46.com/BWSP81.jpg[/img][img]http://www.geoffwelch46.com/BWSP82.jpg[/img][img]http://www.geoffwelch46.com/BWSP83.jpg[/img][img]http://www.geoffwelch46.com/BWSP84.jpg[/img]

The bird was small, with a prinia size body and a longish tail slightly cocked. The crown was brown with a buffish supercilium and a dark brown eyestripe. The back and part of the wings were red-brown but the flight feathers were dark in flight. The throat was whitish grey with the breast darker grey but the belly was yellowish buff (more yellow than the photograph shows) and the flanks and undertail coverts were a more orange colour. The underside of the tail was dark brown – I could not see the upper side or the rump. The legs were pale and the bill dark brown on the upper mandible and pale on the lower.

The call was quite distinctive and made continuously, starting with a long ‘trrrrrrrrrrrrr’ (make the sound with the tongue vibrating on the upper palate) and followed by at least 3 sequences of a short ‘tuk took’, the ‘tuk’ being slightly higher in pitch than the ‘took’. The whole sequence was ‘trrrrrrrrrrrr tuk took tuk took tuk took’, the ‘trrrrrrrrrrrr’ being much longer than the ‘tuk took’.

The bird description could fit Yellowish-bellied Bush Warbler but I have no idea whether the call fits that species.

Any comments please?

[[i] Last edited by wgeoff at 18/08/2010 17:57 [/i]]

I got no proper experience of Yellow-bellied Bush Warbler.  The books are quite confusing except for the call/song, which is very distinctive, at least in summer.  It is interesting to compare this bird to that of Peter's.  On Peter's bird, the chestnut on the crown is very clear.  I think that is good for strong-footed (or Mountain) Bush Warbler.  The bird on this post is really interesting.  The call is very unlike any strong-footed Bush Warbler that I know of.  I think there is a real chance that this is actual a Yellow-bellied Bush Warbler.

HF Cheung

The potential confusion here is that Brownish-flanked Bush Warbler can be yellow on the underparts in first-winter plumage. This is the reason that Yellowish-bellied was formerly on the HK list (it has now been removed, so any claims of YbBW would be a HK first!)

I don't have much experience of YbBW except a few singing birds on the breeding grounds (when, as Ho-fai mentions, the song is very distinctive). Looking at pictures on the OBC website, I think it seems that YbBW has a dark eye-stripe, pale supercilium and short tail - in these respects, the Po Toi bird seems closer to Brownish-flanked. The Po Toi bird also has brownish flanks (which, based on name, seems like it may be a useful feature). Unlike Ho-fai, I don't think the description of the call rules out the alarm call of BfBW, but I don't know the calls of YbBW.

On balance, I think it is most likely that the Po Toi bird is a 1st winter BfBW, but I would welcome any additional comment from anyone with good experience of both species.

Are there any photos of 1st winter Brownish-flanked Bush Warblers anywhere?
The only ones on OBC are Peter Wong's of a juvenile (taken in July) which show the yellow belly but in many other respects are quite unlike this bird (yellow goes right up to the throat, dirty brown flanks not orange buff, dark brown back and wings not red-brown, poorly defined supercillium).

One further point on behaviour. The Po Toi bird was on the ground rummaging around in the grass/weeds all the time. Is this normal behaviour for a Brownish-flanked? Is it normal behaviour for a Yellowish-bellied?