Black-headed Gull
Chroicocephalus ridibundus

Black-headed Gulls are very common and can be seen almost anywhere. The first two are adult birds in Summer plumage when they have chocolate-brown heads.
 

Black-headed Gull  Black-headed Gull

The next two are adult winter birds - most of the dark hood has gone leaving an ear spot and a faint stripe from the eyes over the head. Sometimes, however, not all of the hood disappears.
 

Black-headed Gull  Black-headed Gull

These are 1st-winter birds, as can be told by the brown markings on the wings (carpal bar), orange bill and legs and the usual Winter plumage on the head.
 

Black-headed Gull  Black-headed Gull

These two are 1st-summer birds. The hood is not always perfectly brown and some white feathers may remain on the head.
 

Black-headed Gull  Black-headed Gull

1: Hayling Island, 05/07/2006.
2 and 8: Hogganfield Loch, 22/06/2005.
3: River Exe, Exeter, 01/12/2006.
4: River Thames, Waterloo, 23/11/2006.
5: Radipole Lake RSPB, 26/01/2006.
6: Reading, 06/11/2006.
7: Lodmoor RSPB, 16/06/2006.