YLG - North East Poland (1 Viewer)

[AGDK]

Hello

I saw this bird earlier today.. I'm pretty sure I finally managed to find a real YLG

Leg-colour looks correct
No stripes on the head in wintertime
Clear black mark on P5..

Correct?

 

[lou salomon]

do you have an underwing shot of this bird, AGDK? the only way to conclusively rule out a (much more common) Caspian Gull here. Bill and eye give rather a cachinnans impression. And if I'm not mistaken, p10 tongue in the far (left) wing looks rectangular at its end.

 

[AGDK]

I have this here..

 

[lou salomon]

Oh yes, this helps. It is a YLG indeed!

 

[AGDK]

Great, thanks for confirmation..

Finally I managed to find one around here..

Can you point of more detailed, what makes the underwing important, since I don't see this as a point of decision making in my bird guide..

 

[lou salomon]

AGDK, look at the white tongue on the underside of p10 (outermost primary). It's the white part at the base of the inner web of the feather. In YLG it is short and rounded, in Caspian Gull long and rectangular ended, at least its border line towards the inner edge of the feather is ~90°.
I have drawn the border of that tongue of an average adult Caspian Gull into your YLG-pic, with red. And attached the wingtip of a typical Caspian Gull. There is some degree of variation in wingtip, some have more, some less white but tongue length in (adult) cachinnans usually is at least half of the visible feather or more.

 

[AGDK]

Thanks for your information, Lou.. Highly appreciated all these small gems that is useful for future identification..