Large 1st winter gull, UK, 05 Dec 2021 (1 Viewer)

[GMS]

Bird seen today with many Herring Gulls.
Very big, to the point where I initially thought GBB Gull when it flew in.

Features:

• Almost all white head
• Strong dark bill with paler base
• Some neck streaking but not overly pronounced
• Replaced coverts (more in the right wing), in addition to mantle and scaps
• Underwing appears light in most pics but this depends on the light.
• Primary window is not very pronounced.
• The tail band is massive and the uppertail coverts have some marks.
• Coverts not marked very well

I can't make my mind up with this particular bird so would appreciate some expert input.

Thanks in advance.

 

[KenM]

My very inexpert opinion is thinking 2nd Winter YLGull.

Cheers

 

[lou salomon]

no question about this being a nice male Caspian Gull. everything's there. nice to se newer and older replaced scapulars (more worn diamonds and fresher ones with diffuse greybrown groundcolour). tail pattern is absolutely classic as is the rest of the bird.

 

[KenM]

no question about this being a nice male Caspian Gull. everything's there. nice to se newer and older replaced scapulars (more worn diamonds and fresher ones with diffuse greybrown groundcolour). tail pattern is absolutely classic as is the rest of the bird.

I was thinking that the eye was too big and the bill perhaps too short for Caspian as the only other alternative, presume variability in all things?

PS fwiw, although I haven’t delved too deep into the various papers on “Large White Gull”
Introgression, I did read that in Poland Caspian Gull which has advanced rapidly Westwards since the ‘60’s, no doubt following the metropolitan garbage trail, hybridises with Herring Gull (argentatus?) and YLG where they occur giving a hybridisation rate of c60% with the former!

This might suggest that most of the YLG and Caspian Gulls that reach the UK are “bastards” and being so, are carrying features common to all three species?
Which could explain why ID “confusion” can reign with these large gull species?

For example…seemingly “large” eyed or short legged or billed cachinnans?

Cheers

 

[KenM]

I’ve added further thoughts to this thread in the last post fwiw?

Cheers

 

[lou salomon]

no, Ken. The majority of Caspian Gulls wintering in Western Europe still are pure birds, many of them stemming from their core breeding range in Ukraine. In this bird I see nothing but absolutely nothing even slightly suggesting any other taxon involved. I won't repeat all the important features but once more will link that sophisticated article for cachinnans ID here: www.britishbirds.co.uk/wp-content/uploads/2010/12/Caspian-Gulls-part-1.pdf

 

[KenM]

no, Ken. The majority of Caspian Gulls wintering in Western Europe still are pure birds, many of them stemming from their core breeding range in Ukraine. In this bird I see nothing but absolutely nothing even slightly suggesting any other taxon involved. I won't repeat all the important features but once more will link that sophisticated article for cachinnans ID here: www.britishbirds.co.uk/wp-content/uploads/2010/12/Caspian-Gulls-part-1.pdf

Thanks for that Lou, will immerse myself shortly, however just the one niggle.
“Classics” of both michahellis and cachinnans are straightforward (even I can see that), as I can see the “small” beady eye of a classic adult Caspian, how is it that the “subject” bird and other white-headed 1st/2nd year birds that are imaged all appear to have “larger” eyes, is this gender/age related or come within accepted tolerances for the species?

Cheers

 

[lou salomon]

indeed, the "classic" look with a narrow pencil bill and the small eye placed to the front and towards crown in cachinnans is mainly a female type feature. some males can look big eyed, some even can show a dark smudge around eye like michahellis. but usually you can see it in males too, that if they are seen from the side, standing.

 

[KenM]

Cheers Lou, now I know where I’ve been going wrong.👍