The Large-billed Tern is an unmistakable South American species, and the only member of the genus Phaetusa. The large, heavy bill and striking wing pattern with black primaries, white secondaries, and a gray back, make this bird visually distinctive. During the breeding season, this species can be found along broad, inland rivers and lakes, nesting on the sandy shores in mixed species colonies with Black Skimmers (Rynchops niger) and Yellow-billed Terns (Sternula superciliaris). During the nonbreeding season, some of the population congregates on the eastern coast of South America in coastal mangroves, beaches, and estuaries. Common throughout most of its range, the Large-billed Tern’s main threats are habitat disturbance and egg-collecting.