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.
The Bird Island Nature Reserve in Lambert's Bay, Western Cape, South Africa.
Common murre colony (Farallon Islands).
Eggs collected from a nesting bird colony on Laysan island. Early 1900s.
Nesting Australasian gannets at the Muriwai colony in New Zealand
An auk or alcid is a bird of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The family contains 25 extant or recently extinct species that are divided into 11 genera.
Auk
Auks as painted by Archibald Thorburn
Razorbills are an auk found in the Atlantic Ocean.
Black guillemot (Cepphus grylle, a true guillemot) in summer (front) and winter plumage
