Gull in Switzerland (1 Viewer)

[SternaParadisaea]

Hello,

I saw this gull in Switzerland (Lake Zurich) in a place where the dominant species was the Yellow-legged gull, but with also Caspian and Herring gulls and one GBBG.

In the field I thought it was a Caspian, because it seemed different from the LLG and similar to an adult Caspian gull which was close to it. However, in the pictures I am less sure. Even if the beak seems thin and the legs are less yellow than the majority of LLG (but more yellow that the majority of Caspians), I found the primary projection very little for a Caspian and I am not sure what to conclude from the wing pattern (if it is possible to conclude something with these pictures). The eye was better seen in the field and was dark.

What do you think?

 

[Alexander Stöhr]

Hello,

I agree with you ID from the field, its an adult Caspian gull.

I am not sure, the pp can be judged with confidence with these pictures (foreshortening effect and some wing-shaking action?)

Primary pattern seems good for a Caspian Gull.
I read somewhere, that Caspian Gulls from the eastern part of the breeding range have brighter yellower legs

But please note, that any indication of hybridisation in this Gull is above my paygrade= it looks like a pure Caspian Gull to me=better wait for others to jump in.

 

[SternaParadisaea]

Hello,

Thank you for your fast answer. Yes, after analyzing it, I also find that the wing pattern in very close to this of a typical Caspian. The only argument against a pure Caspian would thus be the weak primary projection. But maybe it is only an impression due to the position of the bird?

Has anyone any other comments?

 

[Steve Lister]

To me there are several things wrong for a pure Caspian Gull. The bill shape. The head shape. The leg length. And maybe the mantle colour.
But I am a bit of a purist when it comes to these things.