Bill long, straight, and strongly hooked at the end, both mandibles being curved downward at the tip; culmen flattened, lateral grooves deep, bifurcating at the dertrum or nail, and the lower branch terminating in a notch in the margin; nostrils in the. groove, basal and linear. A large naked gular pouch. Wings very long and pointed : 1st quill considerably the longest. Tail of 12 feathers, deeply forked. Tarsus very short, feathered ; middle toe longest; web between toes deeply emarginate; claws long, curved, that of middle toe pectinated inside.
Two or three species are known and range throughout tropical seas; two have been taken within Indian limits.
Key to the Species.
a. Bill from gape about 5 inches…………………………F. aquila, p. 338.
b. Bill from gape about 3-75 inches…………………………F. ariel, p. 338.
Frigate or Man-o'-war Birds are well known to seamen from their remarkably powerful flight, and from the use they make of their speed in pursuing Gannets, Gulls, and Terns in order to rob them of their prey. The Frigate-birds live by piracy in tropical seas, just as the Skuas do in colder latitudes; but the species of Frogata do not confine themselves to fish taken by other birds : they often capture flying-fishes, cuttle-fishes, crabs, or even young turtles.