Iceland Gull (Larus glaucoides)
On the Great Lakes, large flocks of herring gulls (Larus argentatus) or ring-billed gulls (Larus delawarensis), interspersed with the odd Iceland gull, are common. Iceland gulls have a commensal, or mutually beneficial, relationship with fishermen, who use the birds' prey-finding abilities to locate large schools of fish.
The Iceland gull is one of the smallest of the ‘large’ gulls, rarely exceeding 55 cm in length and 600 g in weight. This species requires four years to reach full adult plumage, at which time the winter adult’s mantle and wings are light grey, with grey wing-tips, and its head and breast are white, with extensive light speckling. Its flanks, belly, and tail are also white, and its bill is yellow. During its first winter, a juvenile gull has a black bill, and its mantle, wings, head, and underparts are all white, but may have faint buff or light brown speckling.
The Iceland gull breeds on the coasts of Greenland and Baffin Island. This species winters regularly on the Great Lakes and the St. Lawrence Seaway, and on the east coast of North America, from Labrador to Virginia.
The Iceland gull nests are in depressions in the ground and lined them with grass and moss. The two or three eggs have characteristic chocolate-coloured markings.
The Iceland gull is omnivorous, eating a wide variety of fish, crustaceans, mollusks, and other birds' eggs and young. It will also eat berries and carrion. During the winter, the Iceland gull often forages in mixed-species flocks. Unlike some other gull species, they are excellent swimmers, and forage for fish by diving from heights of 2-5 m. Occasionally a bird will become completely submerged during a dive. Iceland gulls also dip their bills into the water, picking food from the surface.