Many birders visit the Dry Tortugas in Florida for the migration spectacle, but the breeding birds are quite impressive as well. There are large colonies of Sooty Terns and the spectacular Magnificent Frigatebird is frequently seen hanging motionless in the air above Fort Jefferson.
Magnificent FrigatebirdFregata magnificens
Frigatebirds are the ultimate gliders among birds, able to hang in the air for hours with hardly a movement of their long, angular wings. Denizens of warm seas, seen soaring over tropical coastlines or perched like gaunt statues on dead trees or navigational towers. They never swim, because their long wings (adapted for soaring) and tiny feet render them unable to take off from water; all their food is snatched from the surface in flight or stolen from other birds.
Field MarksA large black seabird with extremely long, angled wings and a scissorlike tail (often folded in a point). Soars with extreme ease. Bill long, hooked. Male: All black, with red throat pouch (inflated like a balloon when in display). Female: White breast, dark head. Immature: Head and breast white.
Size38-41" (95-103 cm); spread 7-8 feet
Similar SpeciesGreat Frigatebird is a remote possibility. Adult male Great Frigatebird retains light brown wing coverts; female has a whitish throat, red eye-ring.
VoiceSilent at sea. A gargling whinny during display.
RangeGulf of Mexico to southern Brazil; Cape Verde Islands; Baja California to Peru. Summer visitor within dash line.
MigrationPresent year-round in southern Florida; in northern Florida and along Gulf south, more common in summer. Small numbers (mostly immatures) regularly wander inland in Southwest in summer. Rarely wanders north along coasts or far inland.
HabitatOceanic coasts, islands. Occurs over warm waters, usually along coast but also far offshore at times. Also soars inland in coastal areas (for example, crosses isthmus of Panama from one ocean to the other). Very rarely far inland around fresh water. Nests on islands, usually small islands with dense growth of mangroves or other trees or shrubs.
FeedingDiet: Mostly fish. Feeds mainly on small fish, also squid, jellyfish, crustaceans. Takes hatchling turtles, young terns and other birds, sometimes eggs. Also scavenges for scraps around fishing boats, docks.
Behavior: Forages in the air, swooping close to water to take items from on or near surface, making very little contact with water. Never swims. Forages in same way over land, taking prey from beaches without landing. Also feeds by piracy, chasing other birds, forcing them to drop or disgorge their food.
NestingBreeds in colonies. Perched males display (often in groups) by inflating throat pouch to huge red balloon, raising bill high, vibrating partially spread wings, swiveling back and forth, and calling. Females flying overhead are attracted to group, choose one male as mate.
Nest: Site usually in mangroves, trees, or bushes 2-20' above ground or water, sometimes on ground. Nest (built mostly by female, with materials brought by male) a flimsy platform of sticks.
Eggs: 1. White. Incubation by both sexes, probably 40-50 days.
Young: Both parents feed young. Nest is never left unguarded until young are half-grown, as other members of colony will eat eggs or young at unattended nest. Male departs after about 12 weeks, female continues to feed young. Age at first flight 20-24 weeks; female will feed young for additional 16 weeks or more.
ConservationProbably has declined at some tropical colonies. Although known as a common visitor to Florida since the 1800s, not confirmed breeding there until late 1960s (Marquesas Keys). At the Dry Tortugas, began nesting in 1988.