ckn

25/01/2010

This gull was seen at Nam Sang Wai this morning.  It has a broad dark band at tail but it seems not a Black-tailed Gull as its bill is dark instead of yellow and its neck is not short.  Though its forehead looks like a Slender-billed Gull, yet its iris is dark and not white. It has a flat/long forehead and white eye lids as a Pallas's Gull, but its bill is not yellow nor big.

Please advise the ID of this gull.

Sorry for the poorly captured photos.  

HFCheung

Size is difficult to judge. It looks like Vega to me.

HF Cheung

ckn

Quote:

Original posted by HFCheung at 25/01/2010 16:47
Size is difficult to judge. It looks like Vega to me.

HF Cheung

Thanks Dr. Cheung.  

KN

Cyrus

Can anyone tell me why it's not a Heuglin's? Thanks

tsheunglai

Dear K N

Forgive if I mistake about your name.

For the three photos available I would venture that this is possibly a first-winter Yellow-legged
gull mongolicus for the following reasons.

First, the bill looks smaller than that of a Vega. Next, the primaries and tail band look blackish rather than brown. And the tail band contrasts significantly with the upper-tail coverts and a Vega 1st winter does not. Finally the light gray mantle also suggests it be a mongolicus.

It is welcome for someone to point out if my observation is wrong or add their own to mine.

cgeoff

This is a 1st winter Heuglin's Gull.

The dark greater coverts rule out Vega 1y and mongolicus 1y. It has newly-replaced grey inner greater coverts; moult of the greater coverts in the first winter almost never happens in mongolicus, and is pretty unusual in vegae too. The new feathers are greyish, but not very pale; they have the dull, brownish-grey coloration typical of the heuglini-fuscus complex at this stage.

The tail band is actually relatively broad and also blackish, which is good for heuglini.

The bill is not very substantial really. It has a relatively marked 'pinched-in' effect just short of half-way along, and here it is rather narrow.

I think the whiteness of the head and upper body is exaggerated by the photo. However, heuglini can be notably white, especially later in the winter.

Finally, the all-dark bill fits heuglini better at this stage of the winter than it does other taxa occurring in HK.

Interesting bird.

Geoff

bin_go

I have seen a similar (might be the same) one on Jan-23 at Nam Sang Wai. Hope it can help. What is the name of the other one on his right-side?

cgeoff

The right hand bird is 1y mongolicus.

The left hand bird doesn't look the same individual as above. In fact it appears rather large. But I think it's heuglini.

Geoff

ckn

Thanks Cyrus, Sheunglai, and Geoff for their helps in identifying this bird.  I was quite confused at first after searching from and making reference to the books "HK and Southern China Birds" as well as "A Photographic Guide to the Birds of Hong Kong".  

Thank you very much.  

KN