These large black birds are lightly built, with long angled wings and a deeply forked tail. They have a very distinctive, easily identifiable silhouette.
Frigate birds are almost always seen in flight, soaring high above the coastline. They dive for fish or chase other seabirds in flight to make them disgorge their catch. In the Florida Keys, Frigate birds sometimes hang around near fishing boats, waiting to intercept fish being thrown back into the water.
Males have a bright red throat pouch which they inflate during courtship. Females have a white breast patch, and immature birds have white heads and underparts.
Frigate birds are most numerous in Florida from April to September. They roost in colonies, the best known of which are at Seahorse Key near Cedar Key, on islands in Tampa Bay, and in the Indian River-Mosquito Lagoon area.
In the United States, Magnificent Frigatebirds breed only on the Dry Tortugas where about 100 nests can be found on Long Key. However they also breed in the Caribbean and in coastal areas south to Brazil.
The Magnificent Frigatebird (Fregata magnificens) was sometimes previously known as Man O'War or Man of War, reflecting its rakish lines, speed, and aerial piracy of other birds.
It is widespread in the tropical Atlantic, breeding colonially in trees in Florida, the Caribbean and Cape Verde Islands. It also breeds along the Pacific coast of the Americas from Mexico to Ecuador including the Galápagos Islands.
It has occurred as a vagrant as far from its normal range as the Isle of Man, Denmark, Spain, England, and British Columbia.
The Magnificent Frigatebird is 100 cm (39 inches) long with a 215 cm (85 inch) wingspan. Males are all-black with a scarlet throat pouch that is inflated like a balloon in the breeding season. Although the feathers are black, the scapular feathers produce a purple iridescence when they reflect sunlight (in contrast the male Great Frigatebird has a green sheen). Females are black, but have a white breast and lower neck sides, a brown band on the wings, and a blue eye-ring that is diagnostic of the female of the species. Immature birds have a white head and underparts.
This species is very similar to the other frigatebirds and is similarly sized to all but the Lesser Frigatebird. However, it lacks a white axillary spur, and juveniles show a distinctive diamond-shaped belly patch.
The Magnificent Frigatebird is silent in flight, but makes various rattling sounds at its nest.
This species feeds mainly on fish, and also attacks other seabirds to force them to disgorge their meals. Frigatebirds never land on water, and always take their food items in flight.It spends days and nights on the wing, with an average ground speed of 10 km/h, covering 223±208 km before landing. They alternately climb in thermals, to altitudes occasionally as high as 2500 m, and descend to near the sea surface.