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        Discussion Area 討論區 >> Bird Identification 鳥類辨識 >>  Sea Gulls in the Harbour
        
(Message started by: edselchan2 on Feb 13^th, 2003, 9:26am)

Title: Sea Gulls in the Harbour
Post by edselchan2 on Feb 13^th, 2003, 9:26am

More than ten sea gull found in the harbour in between TST and Hung Hom, they have yellow bill and legs, it may be Yellow-Legged Gull, but i am not sure.s

Title: Re: Sea Gulls in the Harbour
Post by miket on Feb 15^th, 2003, 11:44pm

More likely Heuglin's Gull of the form taimyrensis. Yellow-legged Gulls, of the form mongolicus, usually have pinkish legs.

Mike Turnbull

Title: Re: Sea Gulls in the Harbour
Post by Etta on Feb 17^th, 2003, 5:54pm

Is it like this? We are identifyng as well...

Etta

http://netta.cyberec.com/kitesvy/15fb03bd/6091w.jpg
http://www.hkbws.org.hk/fileServer/PhotoG/etta/ettagull01.jpg

Title: Re: Sea Gulls in the Harbour
Post by Mike Turnbull on Feb 17^th, 2003, 7:20pm

Looks like Yellow-legged Gull Larus cachinnans mongolicus to me, due to its fairly pale upperparts, complete lack of head streaking and pinkish legs. I had a probable in flight in East Lamma Channel yesterday; in flight they show a much paler underside to primaries and secondaries than Larus heuglini taimyrensis.

Mike Turnbull

Title: Re: Sea Gulls in the Harbour
Post by Etta on Feb 18^th, 2003, 3:58pm

Dear Mike,

Thanks for the identification.

Best,
Etta

Title: Re: Sea Gulls in the Harbour
Post by YIP Chi Lap [Beta] on Feb 20^th, 2003, 12:30am

I was in the field spotting the bird and thought that its leg looks more like dark pink / dark red in color than yellow --- question: do yellow-legged gulls really have yellow legs?

Title: Re: Sea Gulls in the Harbour
Post by Mike Turnbull on Feb 20^th, 2003, 9:04pm

This is all clearly and understandably getting a bit confusing but the photographed bird is a Yellow-legged Gull of the form mongolicus , because it has pinkish legs, as can be clearly seen in your photograph+the other features mentioned in my earlier post.

The very first message in this thread referred to birds identified as possibly Yellow-legged Gulls because they had yellow legs. My first reply was an attempt to point out that the locally occurring form of Yellow-legged Gull does not have yellow legs. The most common form of "large white-headed gull" in HK, Heuglin's Gull of the form taimyrensis, does in fact have yellow legs and thus this is probably the most likely explanation of what tose first birds were.

Clear??

Mike T.

Title: Re: Sea Gulls in the Harbour
Post by YIP Chi Lap [Beta] on Feb 22^nd, 2003, 1:37am

Thanks. Your reply prompted me to look up bird guides and, very interestingly, a number of them explicitly mentioned something like "the identification of gulls is extremely complex, as all characteristics overlap with rare individual Herring Gulls." [Sibley guide] or "The systematics and identification of all forms of Herring Gull L. argentatus and Lesser Black-backed Gull L. fuscus occuring worldwide have received much attention in recent years. [......] Among the most perplexing taxa of all are those that occur or are likely to occur in South-East Asia, where understanding of the problem is based, to some extent, on guesswork" [Robson, Birds of SEAsia]

Is the following correct?
Larus cachinnans mongolicus: pinkish leg, fairly pale upperparts.
Larus heuglini taimyrensis: yellow leg

What are the most common "large gulls" in Hong Kong?

Title: Re: Sea Gulls in the Harbour
Post by Webmaster on Feb 22^nd, 2003, 9:43pm

for those gull maniac, please take a look at the following site.

http://www.geocities.com/RainForest/Canopy/6181/gulls.html

no easy way out but is of great fun.

Title: Re: Sea Gulls in the Harbour
Post by Mike Turnbull on Feb 23^rd, 2003, 8:41am

Re: Is the following correct?
Larus cachinnans mongolicus: pinkish leg, fairly pale upperparts.
Larus heuglini taimyrensis: yellow leg

Yes, and taimyrensis has relatively darker upperparts. Also, the underwing patterning can be useful indicator (see earlier post) and presence or absence of head-streaking is relevant.

Re: What are the most common "large gulls" in Hong Kong?

L. h. taimyrensis is the dominant form

Id of these gull forms is indeed difficult, and the above are really just indicators, to be used within a known geographical context. That is to say, a simplified statement such as "pinkish leg, fairly pale upperparts" can only be used to indicate a bird is probably mogolicus in our region, not necessarily elsewhere.

Mike Turnbull