Hello,
again I hope for a deeper answer from Lou, Steve, smiths or others, but a feature of older immature YLG (against Herring Gull) is this three-coloured bill:
adult-like bright yellow, a red spot and a contrasting black tip or band.
Therefore, your first bird looks good for a 2cycle YLG to me.
The second bird is harder for me: first jizz is dominated by a long and slender, parallel-edged bill. The position of the eye seems surely shifted by the position of the head, with birds looking away from the camera, but it ads to the impression of a Caspian Gull.
Yes, eye is pale, but bird seems to lack a red eye-ring (many/some? older immature YLG have already developed a deep red one). I see dark shadows on the tertials (as a sign of immaturity?). And the white mirror on p10 is surely too small for a Caspian Gull, even an older immature?
One last thought: I have such a pale, colourless eye in a few birds, that looked otherwise perfectly for a Caspian Gull in nE_Germany.
Conclusion? I hope for others to jump in. But if forced, I would ID this bird as a YLG, too, but prepared to be corrected as always with large Gulls. Thanks!
