Bonaparte’s gulls are plentiful and winter up and down both the east and west sides of Vancouver Island. The smallest gull of North America, the Bonaparte Gull is often described as tern-like in flight.
This gull has narrow wings, a slender, black, pin-like bill, and pink legs. It has a light slate-gray back, with a black line down the trailing edge of the outer wing, and a white belly. The leading edges on the upper surfaces of the outer wing are white. When ln breeding plumage, the adult has a black head and an incomplete white eye-ring.
Non-breeding adults lack the black hood and the adult’s head is white with dark smudges and a dark ear spot. Dark markings on the wings of the juvenile look like a narrow, dark ‘M’ across its back in flight.
Bonaparte’s gulls reach breeding age at two years old. The Bonaparte Gull diet consists of insects, fish, and crustaceans. These gulls breed from Alaska south to southern BC Coast.
On nesting grounds, the Bonaparte’s gulls feed mostly on insects. In coastal areas during the winter season, fish make up the better part of their diet. In a study of the effect of fish-eating birds on inshore fish, Bonaparte’s Gulls were the most efficient predators of the ten species of birds that were part of the study.
Bonaparte’s Gulls nest in small colonies or in single nests. They nest in trees which is very unusual for a species of gulls. They prefer to nest in spruce trees, and nests are built of twigs, moss, lichen, grass, and various types of vegetation. Nests are built 1 to 5 meters off the ground. The female lays up to 3 eggs, which both adults will take turns incubating. They hatch in about 25 days. Both parents help feed the young.