Frigatebirds are seabirds of the family Fregatidae that belong to one of the five extant species of the genera Fregata. The birds are characterized by their black plumage, tails that are long and deeply forked, and bills that are hooked and long. The frigatebird males are distinguished by the presence of a red gular pouch that is inflated to attract the opposite sex during courtship in the breeding season. These birds spend most of their time flying over the oceans in search of prey which they catch from the surface of the ocean. The birds also exhibit kleptoparasitism where they force other birds to regurgitate their food. The birds roost on nests on the ground or low shrubs on ocean islands and breed in colonies. They exhibit one of the longest periods of parental care among the birds of the world. Here is a description of the five extant species of frigatebirds.
5. Magnificent Frigatebird
The Fregata magnificens is the largest species of frigatebird with a length of about 89 to 114 cm. It also has the longest bill among all frigatebirds. The scapular feathers of the male of this species have a purple sheen. The lower sides of the neck and the breast of the female are white. The eye-ring of the female is bluish-gray in color and its wings also feature a brown band. The range of the bird includes the Pacific and Atlantic waters off the coast of the Americas. In the Pacific Ocean, its range stretches from the coastal waters of Mexico to Ecuador and its range in the Atlantic Ocean extends from Florida to southern Brazil. The birds build platform nests on trees and bushes in islands and mangroves. One large egg is laid and incubated by both the male and female for about two months after which the male leaves while the female continues to rear the chick for about a year. The species is listed as “Least Concern” on the IUCN Red List.
4. Ascension Frigatebird
The Fregata aquila is a frigatebird species that shares many of the physical and behavioral features as the other frigatebird species. However, the females of this species usually lack the white patches on the belly and breast and instead have a rusty brown chest and mantle. This species of bird lives in the tropical islands of Ascension and Boatswain Bird Island. The majority of the birds nest on the latter island where they form a large colony spread out over an area of 3-hectares. Earlier, the Ascension Island also had a large population of the Ascension Frigatebird but the growth in the feral cat population on the island exterminated many bird colonies. The species is now recognized as “Vulnerable” by the IUCN.
3. Christmas Frigatebird
The Fregata andrewsi, a frigatebird endemic to the Christmas Island, is similar in appearance to the lesser frigatebird with the exception of a white, egg-shaped belly patch in males and longer, white-colored underwing spurs. Females have a black head and dorsal surface but white belly and collar. The wingspan of the bird is 7.1 feet long. The birds are recognized as a “Critically Endangered” species due to the restricted range and small breeding population of the species.
2. Great Frigatebird
The Fregata minor lives mainly in the Pacific and Indian Oceans but also has a significant population in the South Atlantic. The birds are similar in appearance to the other frigatebirds with a few differences. Males have a greenish glossy sheen on the scapulars and mantle. Females have a white collar, and mottled belly and throat. The birds are as long as 105 cm. Five subspecies of this bird have been recognized. They nest in large colonies of several thousand pairs on the top of trees or shrubs. Mating is seasonally monogamous and the entire period from mating to the end of parenting consumes about a couple of years. The widespread distribution of the bird has led to their classification as “Least Concern.”
1. Lesser Frigatebird
The Fregata ariel is the smallest species of frigatebird (with a length of about 75 cm) that lives over the tropical and subtropical waters of the Indian and Pacific Oceans and are also observed along Brazil’s Atlantic coast. The birds have a brownish-black plumage and narrow, long wings. The mantle and scapulars of the bird exhibit a purple to greenish metallic gloss. The tail of this species is deeply forked. Females have white belly and breast. Males possess a distinct gular sac that is bright red in color and serves the purpose of attracting mates during the breeding season. The birds swoop over to the water surface to catch prey, usually flying fish. There are three subspecies of the lesser frigatebird. The population of this species is presently quite stable and widely distributed and hence the species is labeled as “Least Concern” by the IUCN.