The great frigatebird (Fregata minor) is a large seabird in the frigatebird family. Major nesting populations are found in the Pacific (including the Galapagos Islands) and Indian Oceans, as well as a population in the South Atlantic.
The great frigatebird is a lightly built, large seabird up to 105 cm long with predominantly black plumage. The species exhibits sexual dimorphism; the female is larger than the adult male and has a white throat and breast, and the male's scapular feathers have a purple-green sheen. In the breeding season, the male is able to distend its striking red gular sac. The species feeds on fish taken in flight from the ocean's surface (mostly flying fish), and indulges in kleptoparasitism less frequently than other frigatebirds. They feed in pelagic waters within 80 km (50 mi) of their breeding colony or roosting areas.
The great frigatebird measures 85 to 105 cm (33 to 41 in) in length and has a wingspan of 205–230 cm (81–91 in). Male great frigatebirds are smaller than females, but the extent of the variation varies geographically. The male birds weigh 1,000–1,450 g (2.20–3.20 lb) while the heavier female birds weigh 1,215–1,590 g (2.679–3.505 lb).
Frigatebirds have long narrow pointed wings and a long narrow deeply forked tail. They have the highest ratio of wing area to body mass and the lowest wing loading of any bird. This has been hypothesized to enable the birds to use marine thermals created by small differences between tropical air and water temperatures. The plumage of males is black with scapular feathers that have a green iridescence when they refract sunlight. Females are black with a white throat and breast and have a red eye ring. Juveniles are black with a rust-tinged white face, head, and throat.
Five subspecies are usually recognised:
F. m. aldabrensis Mathews, 1914. West Indian Ocean (Aldabra, Comoros, Europa Island)
F. m. minor (J. F. Gmelin, 1789). Central and East Indian Ocean to South China Sea
F. m. palmerstoni (J. F. Gmelin, 1789). West and Central Pacific Ocean (Caroline Island, Marshall Islands, Hawaiian Islands, Phoenix Islands, Line Islands including Kiritimati (Christmas Island), Marquesas Islands, Tuamotus, Society Islands, Pitcairn Islands and Isla Salas y Gómez)
F. m. ridgwayi Mathews, 1914. East Pacific Ocean (Revillagigedo Islands, Cocos Island, Galápagos Islands)
F. m. nicolli Mathews, 1914. South Atlantic (Trindade and Martim Vaz)