One of the most widespread members of its family, the Gull-billed Tern inhabits both the Old and New Worlds, occurring in a variety of inland habitats, as well as coastal marshes, mudflats and beaches. Adults are moderately large (36 cm length) and may be recognized by their black cap, very white plumage, and thick, black bill. In the New World, Gull-billed Tern nests northward to Southern California (where endangered), Baja California, the coast of mainland western Mexico, and the Gulf Coast of the eastern United States and Mexico. It ranges southward through Central America to both coasts of northern South America. Their prey includes a variety of fishes and crustaceans as well as insects, lizards, and nestlings of other birds. Nesting occurs on natural and artificial islands, isolated beaches, road margins, inland and coastal marshes, lake edges and occasionally on the roofs of buildings.