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