Black-winged Cuckooshrikes on migration

Birding around the Ministry of Public relations and Suan Rotfai in the last week has produced a few notable records, the best being the first Black-winged Cuckooshrikes that I have ever seen in Bangkok during the month of October (one male on 12th at the Dept Public Relations and a female/imm at Suan Rotfai on 15th).  Other highlights included a pair of Peregrines at Dept Public Relations on 7th Oct.

Suan Rotfai provided a few interesting phylloscs on 15th with my first Yellow-browed Warbler of the autumn and an Eastern Crowned Warbler and Pale-legged Leaf Warbler feeding together (the PLLW ID's in the field based on call, with confirmation coming from a sound recording and spectrogram).

Kamchatka Leaf Warbler in autumn

This morning I took a stroll around the grounds around the Dept of Public Relations, a small area of parkland which serves as the best migrant trap near my house.

Whilst checking a patch of trees where I had seen a male Siberian Blue Robin last week I heard an unfamiliar call - a rather flat, nasal "tik" repeated several times. I was really unsure what might be making the call, but knew that it was probably something unusual as I've pretty much mastered the calls of the common residents and migrants that I encounter in Bangkok.  I soon located the bird making the call and was a bit surprised to find that it was a phyllosc! The bird initially gave very poor views - making me think that perhaps it was one of the species I encounter rarely (such as Claudia's Leaf Warbler), but once I got a proper look at it I determined that it was "just an Arctic Warbler".

But what about that call?! It really didn't sound like the explosive, buzzy "tzik" of an Arctic, but from memory it didn't sound much like either Kamchatka or Japanese. The bird promptly shut up, just as I got my iPhone out to make a sound recording (!) so instead I checked the calls in my playlist - it was clearly not the frog-like call of Japanese LW, but actually sounded much closer to Kamchatka than I remembered, although this bird seemed to be giving just the first part of the call (rather than the full "loose" or "dribbly" call found on the recording I had from xeno-canto).  After some pishing the bird showed again and when I played the xeno-canto recording to it, it quickly moved from the high canopy of a tree some 10 meters away to the lowest branches less than two meters in front of me.  It then started calling with the full version of the call, as if to confirm that I was playing it the right tape!

Whilst identification of Kamchatka vs Arctic based on plumage remains very much in its infancy, one thing that I noticed about this bird was how strikingly white the undertail coverts appeared compared with the flanks (and some of my images suggest a very light suffusion of yellow on the undertail coverts, see below).

There is still lots of work to do on these phylloscs, but some useful resources can be found in the links below:

http://www.thaibirding.com/ornithology/kamchatka-leaf-warbler-sakhalin-leaf-warbler.htm

http://www.shanghaibirding.com/2017/06/06/kamchatka/

http://www.shanghaibirding.com/2017/07/01/kamchatka2/

EDIT:

Craig Brelsford from Shainghai birding  has commented:

The research is out there. All we need to do is apply it. 

Birders fall into habits. They often either get into the habit of attempting IDs on the wrong criteria (plumage and bare parts, for ex., in the case of Pale-Sak and Arctic-Kamchatka), or they get into the habit of throwing up their hands and giving up. 

Neither mistake is necessary anymore in the case of Pale-Sak. The research is out there, and it is saying call is diagnosable. All that is left is for is birders to use that new knowledge.

1st October

A walk around Suan Rotfai early morning produced a good sprinkling of migrants including my first Sakhalin Leaf Warbler of the autumn (one, possibly two birds  seen in the field and identified on call), a female-type Stejneger's Stonechat,  a Black-capped Kingfisher, 4 Brown Shrikes (one of which was lucionensis), one Arctic/Kamchatka Warbler (probably Arctic), one Eastern Crowned Warbler and a Taiga Flycatcher.

cristatus Brown Shrike

Black-capped Kingfisher

Stejneger's Stonechat

September summary

Time has been limited for birding and writing up notes - I've been posting more on Twitter and have started recording me records on eBird.

With travel away from Thailand during late August, my first autumn passerine migrant was an Asian Brown Flycatcher on 10th Sept (actually if truth be known my first passerine migrant of Autumn 2017 was was a Red-eyed Vireo in Panama on 26th August!), and this was followed with earliest dates as follows: a male and female Yellow-rumped Flycatcher and a Brown Shrike on 19th Sept, Eastern Crowned Warbler on 21st Sept, Common Kingfisher, Arctic Warbler and Taiga Flycatcher on 27th Sept,  and Siberian Blue Robin (a fantastic male!) and Blyth's Paradise Flycatcher on 29th.