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Fregatidae - Frigatebirds

Frigatebird
Magnificent Frigatebird Fregata magnificens ©Vince Smith (Creative Commons) Website

The Fregatidae or Frigatebirds are a family of seabirds, which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, Fregata. All have predominantly black plumage, long, deeply forked tails and long hooked bills. Females have white underbellies and males have a distinctive red gular pouch, which they inflate during the breeding season to attract females. Their wings are long and pointed and can span up to 2.3 metres (7.5 ft), the largest wing area to body weight ratio of any bird.

Able to soar for weeks on wind currents, frigatebirds spend most of the day in flight hunting for food, and roost on trees or cliffs at night. Their main prey are fish and squid, caught when chased to the water surface by large predators such as tuna. They are referred to as kleptoparasites as they occasionally rob other seabirds for food, and are known to snatch seabird chicks from the nest. Seasonally monogamous, frigatebirds nest colonially. A rough nest is constructed in low trees or on the ground on remote islands. A single egg is laid each breeding season. The duration of parental care is among the longest of any bird species; frigatebirds are only able to breed every other year.

The Fregatidae are a sister group to Suloidea which consists of cormorants, darters, gannets, and boobies. Three of the five extant species of frigatebirds are widespread; the Magnificent Frigatebird, Great Frigatebird and Lesser Frigatebird. Two are endangered the Christmas Island Frigatebird and Ascension Island Frigatebird, and restrict their breeding habitat to one small island each. The oldest fossils date to the early Eocene, around 50 million years ago.

Having the largest wing-area-to-body-weight ratio of any bird, frigatebirds are essentially aerial. This allows them to soar continuously and only rarely flap their wings. One Great Frigatebird, being tracked by satellite in the Indian Ocean, stayed aloft for two months! They can fly higher than 4,000 meters in freezing conditions. Like swifts they are able to spend the night on the wing, but they will also return to an island to roost in trees or on cliffs. Field observations in the Mozambique Channel found that Great Frigatebirds could remain on the wing for up to 12 days while foraging. Highly adept, they use their forked tails for steering during flight and make strong deep wing-beats, though not suited to flying by sustained flapping. Frigatebirds bathe and clean themselves in flight by flying low and splashing at the water surface before preening and scratching afterwards. Conversely, they do not swim and with their short legs cannot walk well or take off from the sea easily.

The average life span is unknown but in common with seabirds such as the wandering albatross and Leach's storm petrel, frigatebirds are long-lived. In 2002, 35 ringed Great Frigatebirds were recovered on Tern Island in the Hawaiian Islands. Of these ten were older than 37 years and one was at least 44 years of age.

Despite having dark plumage in a tropical climate, frigatebirds have found ways not to overheat—particularly as they are exposed to full sunlight when on the nest. They ruffle feathers to lift them away from the skin and improve air circulation, and can extend and upturn their wings to expose the hot undersurface to the air and lose heat by evaporation and convection. They also place their heads in the shade of their wings, and males frequently flutter their gular pouches.

Frigatebirds' feeding habits are pelagic, and they may forage up to 500km from land. They do not land on the water but snatch prey from the ocean surface using their long, hooked bills. They mainly catch small fish such as flying fish, particularly the genera Exocoetus and Cypselurus, that are driven to the surface by predators such as tuna and dolphinfish, but they will also eat cephalopods, particularly squid. Menhaden of the genus Brevoortia can be an important prey item where common, and jellyfish and larger plankton are also eaten. Frigatebirds have learned to follow fishing vessels and take fish from holding areas. Conversely tuna fishermen fish in areas where they catch sight of frigatebirds due to their association with large marine predators. Frigatebirds also at times prey directly on eggs and young of other seabirds, including boobies, petrels, shearwaters and terns, in particular the sooty tern.Vp>They will rob other seabirds such as boobies, particularly the red-footed booby, tropicbirds, shearwaters, petrels, terns, gulls and even ospreys of their catch, using their speed and manoeuvrability to outrun and harass their victims until they regurgitate their stomach contents. They may either assail their targets after they have caught their food or circle high over seabird colonies waiting for parent birds to return laden with food.

There are generally considered to be just 5 species in this family, which are:

Ascension Frigatebird Fregata aquila
Christmas Frigatebird Fregata andrewsi
Magnificent Frigatebird Fregata magnificens
Great Frigatebird Fregata minor
Lesser Frigatebird Fregata ariel

Family Links

Frigatebirds Fregatidae

HBW Family Account

Annotated species list

Frigatebirds Fregatidae

Family Account

Frigatebirds are, indeed, a small family of large piratic birds of tropical oceans. Beyond their long wings and aerial agility, they are best known for their kleptoparasitism on other seabirds.

Frigatebirds Fregatidae

Family Account

Frigatebirds (also listed as "frigate bird", "frigate-bird", "frigate", frigate-petrel")[1] are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, Fregata.

Species Links

Ascension Frigatebird Fregata aquila

Species Account

Sound archive and distribution map.

Ascension Frigatebird Fregata aquila

HBW Species Account

Taxonomy: Pelecanus Aquilus Linnaeus, 1758, Ascension Island. Formerly included all four larger species of genus. Monotypic.

Ascension Frigatebird Fregata aquila

BirdLife Species Account

Ascension Frigatebird Fregata aquila

IUCN Species Status

Ascension Frigatebird Fregata aquila

Species Account

The Ascension frigatebird (Fregata aquila) is a seabird of the frigatebird family Fregatidae which breeds on Boatswain Bird Island and Ascension Island in the tropical Atlantic Ocean.

Christmas Island Frigatebird Fregata andrewsi

Species Account

The Christmas frigatebird or Christmas Island frigatebird (Fregata andrewsi) is a seabird of the frigatebird family Fregatidae which is endemic to Christmas Island in the Indian Ocean.

Christmas Island Frigatebird Fregata andrewsi

BirdLife Species Account

Christmas Island Frigatebird Fregata andrewsi

IUCN Species Status

Christmas Island Frigatebird Fregata andrewsi

Species Account

Sound archive and distribution map.

Christmas Island Frigatebird Fregata andrewsi

HBW Species Account

Taxonomy: Fregata andrewsi Mathews, 1914, Christmas Island, Indian Ocean. Formerly included in F. aquila. Monotypic.

Great Frigatebird Fregata minor

Species Account

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.

Great Frigatebird Fregata minor

HBW Species Account

Taxonomy: Pelecanus minor J. F. Gmelin, 1789, Christmas Island, east Indian Ocean. Formerly included in F. aquila. Subspecies somewhat poorly differentiated. Proposed race peninsulae (from NE Australia) regarded as a synonym of palmerstoni. Five subspecies normally recognized.

Great Frigatebird Fregata minor

BirdLife Species Account

Great Frigatebird Fregata minor

IUCN Species Status

Great Frigatebird Fregata minor

Cornell Species Account

The Great Frigatebird is a member of the pan-tropical, monogeneric family, Fregatidae, the Frigatebirds.

Great Frigatebird Fregata minor

Species Account

Sound archive and distribution map.

Lesser Frigatebird Fregata ariel

BirdLife Species Account

Lesser Frigatebird Fregata ariel

Species Account

The lesser frigatebird (Fregata ariel) is a seabird of the frigatebird family Fregatidae. At around 75 cm (30 in) in length, it is the smallest species of frigatebird. It occurs over tropical and subtropical waters across the Indian and Pacific Oceans as well as off the Atlantic coast of Brazil.

Lesser Frigatebird Fregata ariel

HBW Species Account

Taxonomy: Atagen ariel G. R. Gray, 1845, Raine Island, Queensland, Australia. Genetic data indicate that this species is basal to all others in genus. Three subspecies recognized.

Lesser Frigatebird Fregata ariel

IUCN Species Status

Lesser Frigatebird Fregata ariel

Species Account

Sound archive and distribution map.

Magnificent Frigatebird Fregata magnificens

Species Account

The magnificent frigatebird (Fregata magnificens) is a seabird of the frigatebird family Fregatidae. With a length of 89–114 centimetres (35–45 in) it is the largest species of frigatebird. It occurs over tropical and subtropical waters off America, between northern Mexico and Ecuador on the Pacific coast and between Florida and southern Brazil along the Atlantic coast. There are also populations on the Galápagos Islands in the Pacific and the Cape Verde islands in the Atlantic.

Magnificent Frigatebird Fregata magnificens

Cornell Species Account

A long-winged, fork-tailed bird of tropical oceans, the Magnificent Frigatebird is an agile flier that snatches food off the surface of the ocean and steals food from other birds.

Magnificent Frigatebird Fregata magnificens

BirdLife Species Account

Magnificent Frigatebird Fregata magnificens

HBW Species Account

Taxonomy: Fregata minor magnificens Mathews, 1914, Santa Fe Island, Galapagos Archipelago.

Magnificent Frigatebird Fregata magnificens

IUCN Species Status

Magnificent Frigatebird Fregata magnificens

Species Account

Sound archive and distribution map.

Number of Species

Number of bird species: 5

Useful Reading

Seabirds

by Peter Harrison - Helm 1985

ISBN: 071363510X

Buy this book from NHBS.com

Other Links

Magnificent Frigatebird Fregata magnificens

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