Turner, who wrote on British birds three centuries ago, in describing the great black-backed gull, says that it was called ‘cob’ on the Kentish and Essex coast. It is curious to find that it is still known by this name in the same localities, where it is now very rare. In colour and appearance it closely resembles the lesser black-back, but exceeds it in size, and is nearly twice as heavy--it is, in fact, the largest of the gulls. It is also the rarest species in the British Islands; for although its breeding-sites are not few in Scotland, while others exist on the coasts of England, Wales, and Ireland, its colonies are very small compared with those of other species, and in many cases the breeding-place is occupied by a single pair. Its habits are similar to those of the herring and lesser black-backed gulls; but being so much larger and more powerful, it is more injurious to other sea-birds, whose nests it plunders of their eggs or young. It is also more oceanic, straying to a great distance from land in its search for dead animal matter floating on the waves--a veritable ‘vulture of the sea.’ Its nest is placed, as a rule, on the summit of an inaccessible rock on the coast, or on a small rocky island, and is carelessly formed of seaweed and grass. Two or three eggs are laid, greyish brown, sometimes tinged with olive, with dark brown spots distributed sparingly over the whole surface. Black-headed Gull. Larus ridibundus. Bill and feet red; head and upper part of the neck blackish brown; mantle grey; all the rest, white; the under parts tinged with pink. The black on the head is lost in winter. Length, sixteen inches. * * * * *