Gulls (often informally Seagulls) are birds in the family Laridae. They are most closely related to the terns (family Sternidae) and only distantly related to auks, and skimmers, and more distantly to the waders. Until recently, most gulls were placed in the genus Larus, but this arrangement is now known to be polyphyletic, leading to the resurrection of several genera.
They are typically medium to large birds, usually grey or white, often with black markings on the head or wings. They typically have harsh wailing or squawking calls. They have stout, longish bills, and webbed feet. Gull species are variable in size from the Little Gull to the Great Black-backed Gull.
Most gulls, particularly Larus species, are ground nesting carnivores, which will take live food or scavenge opportunistically. The live food often includes crabs and small fish. Apart from the kittiwakes, gulls are typically coastal or inland species, rarely venturing far out to sea and into surrounding deciduous forests. The large species take up to four years to attain full adult plumage, but two years is typical for small gulls. Large white-headed Gulls are typically long-lived birds, with a maximum age of 49 years recorded for the Herring Gull.
Gulls nest in large, densely packed, and noisy colonies. They lay two to three speckled eggs in nests composed of vegetation. The young are precocial, being born with dark mottled down, and mobile from birth.
Gulls—the larger species in particular—are resourceful, inquisitive and highly intelligent birds, demonstrating complex methods of communication and a highly developed social structure; for example, many gull colonies display mobbing behaviour, attacking and harassing would-be predators and other intruders. In addition, certain species (e.g. the Herring Gull) have exhibited tool use behaviour. Many species of gull have learned to coexist successfully with humans and have thrived in human habitats.