FRIGATE-BIRD, the name given by British sailors to a large sea-bird (Fregata aquila) and its ally F. minor. They form the family Fregatidae, allied to the pelicans (q.v.). The species differ only in size and geographical distribution, F. minor being restricted to the Indian Ocean, while F. aquila is found in the tropics all round the world. They obtain their food largely by robbing other birds, especially the boobies, of their prey and their speed and dexterity upon the wing are astonishing. Usually solitary, the birds breed in large companies on mangrove trees; a single white egg is laid and the nestlings are clad in white down. In the adult, the plumage is dark brown above, and in the males, below also, with a scarlet pouch which is inflated to a large size in courtship; the females are white below.