One-tenth of the world's birds are colonial, choosing to live intimately with others of their kind. Here, a colony of Laysan albatross (Phoebastria immutabilis) in the Midway Atoll National Wildlife Refuge in the North Pacific Ocean comprises more than 500,000 nests.
Some birds, such as penguins, auks, gulls, terns, and swifts, stick together without much interaction, while cooperative groups such as social weavers work together to build one massive nest in which each pair has a separate compartment.
A third type of colonial bird include passerines such as the Florida scrub jay, in which a few adults build a nest in which a couple females lay eggs, and then the entire group helps to raise the nestlings.
U.S. Fish and Wildlife Service / David Patte