ajohn

Today during the bird race our team discovered a Yellow-streaked Warbler near Ping Che in the northern NT.
We had initially identified the bird as possibly Radde's Warbler, but fortunately the bird was singing and when we checked the songs on xeno-canto later we were able to confirm ID as Yellow-streaked. The song was a series of fairly short, accelerating notes followed by a short trill; this can be heard at http://www.xeno-canto.org/asia/b ... ler&species_nr=

Directions (unfortunately the location is not easy to describe!):
The bird was along the road connecting Ping Yeung village to Wo Keng Shan Road.
From Wo Keng Shan Road (just before the NENT landfill) follow the road through some plantation woodland. After the track comes out of the woodland, it bends around the base of the small hill. Before you reach the burnt area, on the left is a single house. The bird was alongside the track, initially just above the track but it later flew down towards the house. It was perching mostly in low trees and singing frequently.

brendank

John, for future reference, was there anything helpful in terms of visual identification or did this look like a completely typical Radde's Warbler if it wasn't singing?

ajohn

It was initially very close but slightly silhouetted against the sky, and I thought that the structure was closer to Dusky - the bill was not as heavy or the legs as thick as I would expect of Radde's. This was one reason my mind had started to consider Yellow-streaked.
It then flew overhead and downhill to a point where it was not against the sky and disappeared for a couple of minutes. When it hopped out again, I thought it looked very similar to Radde's in terms of plumage but the view was so short that I didn't manage to get much by way of detail.

sdavid

Still there this morning singing and showing well.

Thanks for getting such detailed directions out as well.

brendank

Yellow-streaked Warbler heard singing at 800 about 3-4 times. Didn't sing again after that. We didn't see it.

It would be helpful if anyone who saw it yesterday could describe any relevant details especially in how it differed from a Radde's Warbler. This may be an overlooked species in Hong Kong and there are very few good photos of the species that I can find from internet searches so any information would be welcome.

ddavid

Brendan -

Paul Leader wrote a paper on Radde's/Yellow-streaked/Dusky Warblers in the 1994 HK Bird Report - if you can get hold of a copy!

Dave

tmichael

I saw many Yellow-streaked Warblers in Burma last week. I've seen them there and in HK before, but perhaps spent a bit longer looking at them this time, as it was a non-birding trip really, and they were one of the most easily seen birds in hotel grounds at Bagan.

They are in jizz terms to me more Dusky-like (though there's actually overlap with Radde's at the top end of the bill-base depth range, I believe). Anyway to get to the main point, I thought the first one was a Dusky, though it did look an odd tone, but then I noticed it had a well-defined tapering super behind the eye (wrong for Dusky), while in front of the eye the super was basically quite well-defined too, so wrong for Radde's.

I did have the latest edition of Robson with me, and it actually confirmed this feature - maybe just me but I can't remember having this quite simply observed distinction pointed out before and have tended to think the super in front of the eye was rather indistinct like Radde's.

Have not checked photos since I returned, but this seems to me a good distinction.

And they do give a bunting-like 'tzik'.

Mike Turnbull

[ Last edited by tmichael at 11/04/2012 22:08 ]

ajohn

There is a summary of the features Paul Leader thinks are useful on this thread: http://www.hkbws.org.hk/BBS/viewthread.php?tid=9047. There are some pictures on OBI: http://orientalbirdimages.org/search.php?Bird_ID=1830

Given that Dusky Warbler is the 'default' species of this group in HK, I think that familiarity with that species is very important, including familiarity with the range of variation. The Ping Che bird struck me as being similar in structure to Dusky but with a head pattern unlike that I have ever seen on Dusky, and more similar to Radde's (particularly the long supercilium, white behing the eye).

I wonder if habitat may be a useful indicator as well. The Ping che bird was in low shrub on the edge of a dry hillslope. I have seen Yellow-streaked in similar habitat in China. Dusky will use this habitat in HK (and was present in the same area at Ping Che) but in  my experience Radde's tends to be found in more mature wooded areas.

But as Mike mentioned voice is really the key. I was fortunate that the Ping Che bird was singing. It was this song which initially drew my attention and which finally led to clinching the ID. Again, familiarity with the song of Dusky (there are many singing at the moment) is useful in this respect. Knowing the calls of the species would also be crucial to picking out Yellow-streaked at other times.

brendank

I've just gotten a hold of Paul Leader's article and the photos suggest that Yellow-streaked is rather similar to Dusky in structure but closer to Radde's in plumage.  I agree with John that vocalizations should be the key feature. In Hong Kong, my experience has been that Dusky Warblers are very vocal while Radde's Warblers are very quiet. I've watched several Radde's Warblers for extended periods with out hearing any call notes. So I wonder how often Yellow-streaked Warblers give call notes? It is a rare occurrence indeed to be able to hear the song of Yellow-streaked.

cgeoff

Certainly much less frequently than Dusky Warblers, but probably not that different from Radde's, or perhaps slightly more frequently.

However, note that vocalising behaviour of the bird at Ping Che is probably unrepresentative of the species, given how much playback has been used to lure the bird out.

Certainly, this type of record, a singing rarity on passage, is pretty unusual in HK as we are so far south of the breeding grounds of many of these species. Many species pass through a month or so before they establish territories in earnest.

GeoffC

ajohn

The Ping Che bird was singing continuously on the day it was found, when it was not affected by the use of tapes. I don't know the extent to which tapes were used in subsequent days, but it is possible this did not increase the frequency of singing. However, the bird wasn't certainly heard to call during the period of observation.

I had actually assumed that, rather than being a passage bird, this could be an individual which has overwintered undetected in this location (where there are few birdwatchers), and that it had started to sing as spring arrived, in the same way as Dusky Warblers. It's not so unusual for some Phylloscopus to sing while in HK despite being distant from breeding grounds (Dusky, Yellow-browed, Pallas's and Arctic/Japanese all sing relatively regularly).