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First-winter Caspian Gull Larus cachinnans
First-winter Caspian Gull, 3rd December, 1999

Even on distant and poor views, the shape, posture and plumage makes a first-winter not too much of a problem to pick out.

First-winter Caspian Gull, 3rd December, 1999

On the underwing, there is minimal marking. Compare this with the other first-winter Caspian Gull with wings raised