THESE back-headed gulls lined up on a wall at Swinsty Reservoir were photographed by Calum Naylor.

The RSPB says the bird is more chocolate-brown rather than black, and in fact for much of the year has a white head.

It is not a 'seagull' as such in that it is found commonly almost anywhere inland, says the charity, and is a 'sociable, quarrelsome, and noisy bird'.

"It is usually seen in small groups or flocks, often gathering into larger parties where there is plenty of food, or when they are roosting."