Auk in the context of Brachyramphus

A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony. Colonial nesting birds include seabirds such as auks and albatrosses; wetland species such as herons; and a few passerines such as weaverbirds, certain blackbirds, and some swallows. A group of birds congregating for rest is called a communal roost. Evidence of colonial nesting has been found in non-neornithine birds (Enantiornithes), in sediments from the Late Cretaceous (Maastrichtian) of Romania.

Gulls and seagulls are seabirds of the subfamily Larinae. They are most closely related to terns and skimmers, distantly related to auks, and even more distantly related to waders. Until the 21st century, most gulls were placed in the genus Larus, but that arrangement is now considered polyphyletic, leading to the resurrection and revision of several genera. An older name for gulls is mews; this still exists in certain regional English dialects and is cognate with German Möwe, Danish måge, Swedish mås, Dutch meeuw, Norwegian måke/måse, and French mouette.

Gulls are usually grey or white, often with black markings on the head or wings. They normally have harsh wailing or squawking calls, stout bills, and webbed feet. Most gulls are ground-nesting piscivores or carnivores which take live food or scavenge opportunistically, particularly the Larus species. Live food often includes crustaceans, molluscs, fish and small birds. Gulls have unhinging jaws that provide the flexibility to consume large prey. Gulls are typically coastal or inland species, rarely venturing far out to sea, except the kittiwakes and Sabine's gull. 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 usually long-lived birds, with a maximum age of 49 years recorded for the European herring gull.

Puffins are any of three species of small alcids (auks) in the bird genus Fratercula. These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crevices among rocks or in burrows in the soil. Two species, the tufted puffin and horned puffin, are found in the North Pacific Ocean, while the Atlantic puffin is found in the North Atlantic Ocean.

All puffin species have predominantly black or black and white plumage, a stocky build, and large beaks that get brightly colored during the breeding season. They shed the colorful outer parts of their bills after the breeding season, leaving a smaller and duller beak. Their short wings are adapted for swimming with a flying technique underwater. In the air, they beat their wings rapidly (up to 400 times per minute) in swift flight, often flying low over the ocean's surface.

The Atlantic puffin (Fratercula arctica), also known as the common puffin, is a species of seabird in the auk family. It is the only puffin native to the Atlantic Ocean; two related species, the tufted puffin and the horned puffin, are found in the northeastern Pacific. The Atlantic puffin breeds in Russia, Iceland, Ireland, Britain, Norway, Greenland, Newfoundland and Labrador, Nova Scotia, and the Faroe Islands, and as far south as Maine in the west and France in the east. It is most commonly found in the Westman Islands, Iceland. Although it has a large population and a wide range, the species has declined rapidly, at least in parts of its range, resulting in it being rated as vulnerable by the IUCN. On land, it has the typical upright stance of an auk. At sea, it swims on the surface and feeds on zooplankton, small fish, and crabs, which it catches by diving underwater, using its wings for propulsion.

This puffin has a black crown and back, light grey cheek patches, and a white body and underparts. Its broad, boldly marked red-and-black beak and orange legs contrast with its plumage. It moults while at sea in the winter, and some of the brightly coloured facial characteristics are lost, with colour returning during the spring. The external appearances of the adult male and female are identical, though the male is usually slightly larger. The juvenile has similar plumage, but its cheek patches are dark grey. The juvenile does not have brightly coloured head ornamentation, its bill is narrower and is dark grey with a yellowish-brown tip, and its legs and feet are also dark. Puffins from northern populations are typically larger than those in the south, and these populations are generally considered to be a different subspecies.