It chooses for its breeding-quarters some grassy slope on the top of the cliffs or on an islet in one of the numerous firths in the west of Scotland. In Ireland it is generally distributed and nests sparingly round the coast. In all its habits this species so closely resembles the Herring Gull that further description is unnecessary.
The adult only differs from the preceding species in being black on the mantle and wing coverts, and in the colour of the legs, which are yellow. Length 22 in.; wing 16 in.
It is almost impossible to distinguish the young of this species in their first autumn.
THE GREATER BLACK-BACKED GULL
Larus marinus, Linnæus
This species may be found during the winter on almost any part of our shores, but it is by no means so abundant as the Herring Gull.
As a breeding species in England it is rather scarce, chiefly owing to lack of suitable places, but in Scotland it is abundant. It is a bold and majestic species, with a fine soaring flight, but we must acknowledge that it is terribly destructive to weakly lambs and young water-fowl. Practically omnivorous, nothing comes amiss to this rapacious bird, and its food consists largely of carrion and other refuse of the shore. Although it has often been denied, this and other species of Gulls can completely immerse themselves and pick up food from the bottom in at least three feet of water, and we have repeatedly observed them do so in captivity. Having marked some food at the bottom of the water, they rise to a height of about four feet and forcibly precipitate themselves into the water with half-open wings; they are nevertheless extremely buoyant, and occasionally bob up on to the surface again before they have attained their object.
An isolated “stack” or islet in a loch is commandeered by a pair of these birds for their summer home. The nest, composed of grass and rubbish, is usually placed on the highest point. They lay two or three eggs, which are stone buff in colour, blotched and spotted with light brown and grey.
The most usual note is a deep “ow, ow, ow.” In plumage the adult is almost the counterpart of the preceding, but the legs are flesh-coloured. Length 23 in.; wing 19 in.
The young are mottled and barred with various shades of brown and buff, but are rather lighter in colour than those of the Herring Gull. The adult plumage is assumed by precisely the same stages as in the other species, and they may occasionally become fully adult in their third summer.