ckn

12/1/2009
Nam Sang Wai

Note: Thanks HKBWS's experts Geoff and John in helping me to identify this gull.(Edited on 14/1/2009 19:52hr.)

#1   D300 + 600/4VR


#2   D300 + 600/4VR + 1.4X


#3   D300 + 600/4VR + 1.4X


[ Last edited by ckn at 14/01/2009 19:53 ]

John Holmes

Large Gulls can be difficult, but I think this is Yellow-legged Gull , Larus (cachinnans) mongolicus.

As described in Lam, Viney and Phillipps "The Birds of Hong Kong and South China" it is "larger-billed, bulkier and significantly paler than Heuglin's Gull" and has "extensive black in the wing tip with large white mirrors..."

According to the book "Gulls of Europe, Asia and North America" by K.M.Olsson and H.Larsson ( and as Geoff Carey has pointed out on this forum in previous winters ) "mongolicus" moults later than other races of Yellow-legged Gull. the other races moult the outer primaries (P.9 & P.10) in December.... here is this bird moulting the outer primaries in January (arrowed in my photo from yesterday at NSW).

I would have posted MY photo earlier, but I had to read up on big gulls... never being quite sure about them !

[ Last edited by John Holmes at 13/01/2009 11:28 ]

ckn

Quote:

Original posted by John Holmes at 13/01/2009 11:16
Large Gulls can be difficult, but I think this is Yellow-legged Gull , Larus (cachinnans) mongolicus.

As described in Lam, Viney and Phillipps "The Birds of Hong Kong and South China" it is "larger-b ...

Thanks John.  This was the same bird we photographed on Monday morning.  I agree it is quite difficult for me (a green birdwatcher) to identify gulls, though I had searched against the same book "The Birds of Hong Kong and South China" by Lam, Viney and Phillips.  


Subject name has been amended accordingly.  Thanks again.  

cgeoff

I think all of the photographs above are of Heuglin's Gull.

1. All birds show fairly extensive, moderately heavy greyish-brown mottling around the head/neck. While mongolicus can show this very early in the winter, by this time usually what is left is remnant faint spotting, and it appears notably more white-headed than other large gulls in HK.

2. John is right to point out the importance of primary moult timing. However, while mongolicus moults a month later than nominate cachinnans, it is still complete before the turn of the year, and usually by end November. Thus, any bird in active primary moult in the first three months of the year is very likely to be Heuglin's. John's photo of a bird still growing the outer 3 primaries is typical of Heuglin's at this time of year.

3. The first three photos in particular show the relatively dark upperparts typical of Heuglin's. Although John's picture shows a rather paler bird, this is because of the light. It's still not as pale as I would expect for mongolicus.

4. The bill shape of these birds is also typical for Heuglin's. In contrast, mongolicus has a heavier, more parallel-sided bill shape.

It's great to see these large gull photos, especially good ones such as these.

Geoff

John Holmes

Geoff is likely to be correct.
My apologies to you, K.N.Cheung...you were right the first time !
I "give up" on big gull identification !

John

ckn

Thanks both Geoff and John in helping me to identify the gull.   I add herebelow a few more higher resolution photographs (1024 pixels wide) of this gull.

Thanks.  

KN

tmichael

These are fantastic pictures and it is great that within our Society we can have "high level" discussions about birds like this, or nightjAR/kestrels, or hawfinches, wild or otherwise.

All great stuff, and so much better than painful bi-lingual threads over whether people may or may not be permitted to be allowed to know the location of, say, a vagrant shrike.

Mike Turnbull