Yellow-legged Gull question. UK, 30 Sep 21 (1 Viewer)

[GMS]

I had this down as a 1st winter YL Gull based on structure, bill, tail pattern, moult of scaps and lesser coverts, dark underwing, greater coverts pattern. Depending on wing position, the primary window seems more pronounced than I'd expect for a typical YL Gull. Any thoughts? I don't see too many of these, so not that familiar with variability.

 

[Alexander Stöhr]

Hello,
like you i would like to hear expert opinions: my thought, wenn seeing these pictures
it looks better for Caspian Gull by

• broad washed out pale tips of the tretials with inner pale markings
• quite small, rounded head with slender bill
• many second generation feathers on upperparts with the anchor pattern for Caspian Gull, that doesnt distract from the impression from pale silvery grey upperparts
• it is easy to see 1 cy Caspaian Gulls with purer white head and body than this bird here. See for example here: (Prenlau, NE-Germany, 19.09.2021)
• edit: is the tail band too broad for a YLG, I get this impression in the last picture
• do I see pale lozenges in the inner primaries. I think so.

https://flic.kr/p/2mwPa2B

https://flic.kr/p/2mwTetZ

https://flic.kr/p/2mwPa4v

But I agree with you, that it doesnt look like an iD book bird: therefore: I hope that I am right or happy to be corrected, but is this bird within acceptable limits for a 1 cy Caspian Gull?
With many birders aware of the new ID problem 1 cy Herring x Caspian Gull-hybrid vs 1 cy YLG no (thanks to all here and elsewhere), this isnother example, at least for me.

Or is it a 1 YLG? If you search at gull-research, you find birds like this Gull Research Organisation When writing this, I realized, that I have yet to learn so much.

 

[GMS]

Thanks as always Alexander. I've attached one more. I had pondered Caspian but the darkish underwing and lack of obvious 'wingbars' put me off.

 

[Alexander Stöhr]

Hello,
thank you for the new picture. Please note that this is not a confident answer. Like you, there are some features off for a (pure-looking) Caspian Gull:

• distinct barring to grater coverts
• streaking on the rear head and a sugestion of a dark mask
• lack of obvious wingbars as you have said
• I wish the axillaries were unbarred

And I think thats the question here: a pure Caspian Gull within accepted (=defined by experts) limits, a Caspian x Herring Gull? Or maybe a YLG and I am wrong? See this excellent pictures, YLG is very variable: 1st winter Yellow-Legged Gulls, Venice

 

[GMS]

Hi Alex, had some additional feedback agreeing with your ID. Where I live Herring Gull is very common and hence there is familiarity with the huge variability within the species. No doubt the same variability is true for Caspian and YL Gull but because they are much less common any feature different to a 'typical' individual makes confident identification much more difficult (at least for me!)