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Kumlien's / Thayer's Gull??, Staffordshire (1 Viewer)

Phil Andrews

It's only Rock and Roller but I like it
United Kingdom
The roost watchers at Chasewater would appreciate any thoughts regarding this second winter gull, originally identified as a Kumlien's but with Thayer's now suggested.
 

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And one final image (all taken this evening - photos courtesy of Keith Whitehouse)
 

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I've no direct experience of Thayer's Gull, but a few things don't fit based on my limited knowledge/experience.

I would expect the wing coverts for example, to be much plainer than this bird's (notice in pics 2 & 3 how boldly marked they are) and the tail to be predominantly plain & dark. So for me, you need to exclude a 3cy Herring Gull (what I think this is) before considering a Thayer's/Kumlien's.

The bird in post #2 is a different bird (2cy Herring Gull).
 
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Phil - I take it the last image has been uploaded incorrectly? I'm sure others who are far more experienced will be able to add far more detail, but shouldn't Thayer's show a darker and broader subterminal tail bar as well as barred uppertail coverts? Also not sure that a window in p10 is good for Thayer's - see http://gull-research.org/thayers/2cymay.html.
 
Phil - I take it the last image has been uploaded incorrectly? I'm sure others who are far more experienced will be able to add far more detail, but shouldn't Thayer's show a darker and broader subterminal tail bar as well as barred uppertail coverts? Also not sure that a window in p10 is good for Thayer's - see http://gull-research.org/thayers/2cymay.html.

Your link isn't working for me Daniel, but a p10 mirror is at least possible on 2nd winter Thayer's (if uncommon): http://gull-research.org/thayers/thayers2cy/2cydec03.html

There aren't many examples of early 3cy birds on the GRO site, so I've linked a late 2nd cy bird, which shouldn't look too different. I can certainly see more than a passing resemblance to the subject bird, but IMO the key features aren't right for Thayer's.

edit: my own link isn't working for me either-uploaded in my usual way, so perhaps something wrong at my end?!! (but does work using my phone wtf!)
 
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#2 shows a 2cy HG, and the bird in #1 is also a herring gull, a 3cy. much too bulky, strong billed and wrong pattern. i guess it's a nominate argentatus with its p10 mirror (not 'window' as said above) of an isabelline type - paler, more washed out pattern than usual.
 
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