Glaucous Gull (Larus hyperboreus)

While most gulls are scavengers, the glaucous gull is more predatory and can catch auks, plovers, small ducks, as well as lemmings!

Description

Glaucous gulls average 70 cm in length and can weigh up to 1.6 kg, with males being somewhat heavier than females. Juveniles in their first winter have a pale mantle or upper parts, and pale wings with brownish barring. Their head is light brownish-grey or buff, the underparts are uniform brownish-grey, and there may be faint bars on the sides of the breast and flanks. These birds require four years to reach maturity and by the time they are adults, their colouring has changed significantly. In the adult bird, the mantle and wings are very pale grey, and the wings have a white leading edge and white tips. The mature gullís head is white, with brownish streaking, its underparts are white, with some streaking on the upper breast, and its tail is also white.

Distribution

Glaucous gulls breed on the High Arctic coastal tundra, in Alaska, on the Canadian mainland, and in Greenland and the Queen Elizabeth Islands. Populations remain year-round in western Alaska, and in northern Quebec and Labrador. The other populations migrate to the east and west coasts of North America, north of central California in the west, north of Virginia in the east, and to the Great Lakes.

Ecology

The nest of the glaucous gull is built within a depression on a rock ledge and is lined with fine grass, or alternatively, consists of a mass of sod and seaweed. The female lays two to three brown eggs bearing irregular, dark brown spots.

The glaucous gull eats mainly fish, small rodents, the eggs and young of other seabirds, aquatic invertebrates and carrion. It may also supplement its diet with berries. It scouts for food primarily by patrolling at low altitude over water, but will also sometimes pirate food from other birds by chasing them until they disgorge the contents of their crops.