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Gull identification UK (1 Viewer)

GMS

Well-known member
Hi,

had this down as a 1st winter Caspian Gull but some features not quite right.
Good for Caspian are (in my opinion):
White head, chest and belly white. Sides marked quite heavily.
Marked side and back of neck (collar)
New, grey (quite heavily marked) scaps and mantle
Underwing light coloured
Prominent tail band
Some new feathers coming through on coverts
Inner greater coverts are darker but greater coverts are more heavily marked, then I've seen in any other 1st winter bird.
Primary window reasonably prominent.

Overall it just looks a bit scruffy and the 'normal' steps between the scaps/mantle, lesser/median coverts and greater coverts.

Any thoughts welcome.
 

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I think your thoughts are spot on. It's clearly got a lot of Caspian genes in it, but whether it is a pure bird is perhaps open for debate.

Compared to more textbook examples, the following features indicate that another species might be involved:

Rather compact, Herring Gull-like structure, including a relatively short bill.
Brown-toned underwing coverts
Tertial fringes show some notching (like many Herring Gulls)
Scapulars are patterned rather like many Herring Gulls too

I'm not sure that the greater coverts are so unusual for Caspian, and it's worth remembering that if you looked at hundreds of Herring Gulls, there is huge variation between individuals, so why not the same with Caspian Gulls?

Often we are only happy to accept birds that are close to 'the norm' as proper Caspian Gulls, and I sometimes wonder whether we disregard birds too quickly that don't fit this pattern.

Your bird clearly has a lot of positive features, many of which you've mentioned above, not least the extensive covert moult which would be too advanced for any Herring Gull at this time of year, but my gut is saying that this is probably one of those birds that originate from a mixed colony, perhaps in East Germany or Poland?

I'd call it a 'Caspian Gull' on balance; it's not quite the real deal though. Great find :t:
 
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For me the head and bill combined look much more like Herring Gull.

On a second look this morning it does look even more Herring-like to my eyes, but I doubt it can be written off as just a pure Herring Gull.

I don't think any HG would have as many replaced median and lesser coverts already, so a hybrid seems most likely.
 
3 features that i associate with the Caspians i have seen do not stand out on this bird:

Proportions of head and bill - lack of longish bill compared with ‘pear-shaped’ head.

Leg length - not long enough but the bird is in water.

‘Long’ appearance of the bird.

All the above ‘fwiw’ as i am no expert.

Laurie:t:
 
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