Frigate Bird, or Man-o'-War Bird, a large, long-winged seabird related to the pelicans. There are five living species. All, like the sailing ships after which they were named, are noted for speed and aggressiveness. They are found on tropical islands and along warm coasts bordering the South Atlantic and Pacific, and the Indian Ocean. One species is found only on Ascension Island.

The magnificent frigate bird is the largest species. It grows to 40 inches (1 m) in length, including its 17-inch (43-cm) deeply forked tail, and may have a wingspread of 7 feet (2.1 m). Its five-inch (13-cm) bill is sharply hooked at the tip. The male is black, glossed with green, but its inflatable throat pouch becomes deep red or brilliant orange during the mating season. The female, larger than her mate, is brown with white underparts. The magnificent frigate bird is sometimes seen along the coasts of Louisiana and southern Florida, but does not nest there.

In spite of their superior flying ability, frigate birds rarely venture more than 75 miles (120 km) from shore. They seldom enter the water. They feed on flying fish, jellyfish, and other marine animals they catch in their bills at the ocean surface. They are noted for their habit of attacking smaller birds such as gannets and terns, forcing them to disgorge food, which the frigate birds snap up in mid-air.

Frigate birds nest in colonies on uninhabited islands. Their short, weak legs make them awkward on land. The female lays a single white egg in an untidy nest of sticks set between rocks or in low bushes. The parents take turns guarding the egg, and later, the nestling, because other frigate birds might eat the egg or nestling.

Frigate birds make up the family Fregatidae. The magnificent frigate bird is Fregata magnificens; the Ascension Island species, F. aquila; the smallest frigate bird, F. ariel.