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
Thayer's gull Thayer's gull Thayer's gull ("Larus glaucoides thayeri") is a subspecies of the Iceland gull. It is a large gull native to North America that breeds in the Arctic islands of Canada and winters primarily on the Pacific coast, from southern Alaska to the Gulf of California, though there are also wintering populations on the Great Lakes and the upper Mississippi River. The species has occurred as a vagrant to Japan, Denmark, and other parts of western Europe. Somewhat intermediate between American herring gull and Iceland gull in habit and appearance and at times considered conspecific with either species, the adult