The largest gull in the world. It is bulky, and has a powerful bill. The adults have blacker wings and back than the smaller Lesser Black-backed Gull. The conspicuous white spots at the tips of the primaries are often referred to as "mirrors". The legs are pinkish, and the bill yellow with a red spot. It has a heavy flight and can look quite hunched when perched. They take at least four years to reach maturity. Young birds have scaly black-brown upperparts, and a neat wing pattern.

Found around the coasts in the breeding season. At other times of year it can be found wherever gulls congregate - at reservoir roosts, rubbish tips inland, and bays and harbours.

All year round - found inland most in winter.

17,000 breeding pairs with 76,000 birds over wintering.

Fairly common winter visitor, scarce at other times.