Gull the exceptions being Sabine's gull and swallow-tailed gulls, which have forked tails, and Ross's gull, which has a wedge-shaped tail. Gulls have moderately long legs, especially when compared to the similar terns, with fully webbed feet. The bill is generally heavy and slightly hooked, with the larger species having stouter bills than the smaller species. The bill colour is often yellow with a red spot for the larger white-headed species and red, dark red or black in the smaller species. The gulls are generalist feeders. Indeed, they are the least specialised of all the seabirds, and their morphology allows for
Ivory gull from the Arctic than adults. Ivory gulls migrate only short distances south in autumn, most of the population wintering in northern latitudes at the edge of the pack ice, although some birds reach more temperate areas. It takes fish and crustaceans, rodents, eggs and small chicks but is also an opportunist scavenger, often found on seal or porpoise corpses. It has been known to follow polar bears and other predators to feed on the remains of their kills. The ivory gull breeds on Arctic coasts and cliffs, laying one to three olive eggs in a ground nest lined with moss,