This elegant tern is known for its long tail and slender orange bill. During the breeding season, adults have a full black cap and a dark belly. In non-breeding plumage, adults have a paler belly and only a solid black nape patch, with the black crown reduced to mottling. It can be similar to the larger, bulkier River Tern, but the Black-bellied Tern is generally distinguished by its shorter, thinner bill and its black belly in breeding plumage. Additionally, the River Tern has patchier black on the head in non-breeding plumage. The Black-bellied Tern breeds on sandy or gravel islands in rivers and lakes, but forages across a variety of wetland habitats. Its call is a squeaky “wee’tew!” note. This species is uncommon and currently declining.