Magnificent frigatebird

The magnificent frigatebird was originally considered to belong to the species Fregata aquila but in 1914 the Australian ornithologist Gregory Mathews proposed that the magnificent frigatebird should be considered as a separate species with the binomial name Fregata magnificens.^[2] Of the four other species within the genus Fregata, genetic analysis has shown that the magnificent frigatebird is most closely related to the Ascension frigatebird (Fregata aquila).^[3]


There are two subspecies:


Prior to 2022, both these subspecies were considered synonymous with one another and grouped under F. m. magnificens. However, they were split by the International Ornithological Congress in 2022 based on a 2011 study which examined genetic and morphological variation in magnificent frigatebirds, finding both expected and also highly unexpected results. As predicted by the flight capacity of the species, the authors found signatures of high gene flow across most of the distribution range. This included evidence of recent gene flow among Pacific and Atlantic localities, likely across the Isthmus of Panama. This geological formation is a strong barrier to movement in most tropical seabirds. However, the same study also found that the magnificent frigatebird on the Galápagos Islands is genetically and morphologically distinct. Based on this study, the Galápagos population has not been exchanging any genes with their mainland counterparts for several hundred thousand years.^[4]

Distribution[edit]

The magnificent frigatebird is widespread in the tropical Atlantic, breeding colonially in trees in Florida, the Caribbean and also 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, Nova Scotia, the Magdalen Islands, and British Columbia.

The magnificent frigatebird is the largest species of frigatebird. It measures 89–114 cm (2 ft 11 in – 3 ft 9 in) in length, has a wingspan of 2.17–2.44 m (7 ft 1 in – 8 ft 0 in) and weighs 1.1–1.59 kilograms (2 lb 7 oz – 3 lb 8 oz).^[13] 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 to the male great frigatebird's 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.


It spends days and nights on the wing, with an average flapping rate of 2.84 beat per second,^[14] ground speed of 10 km/h (6.2 mph), covering up to 223 km (139 mi) before landing. They alternately climb in thermals, to altitudes occasionally as high as 2,500 m (8,200 ft), and descend to near the sea surface.^[15]

Status[edit]

The Galápagos population of the magnificent frigatebird may warrant a separate conservation status. This small population of genetically unique magnificent frigatebirds is vulnerable. Any catastrophic event or threats by humans could wipe out the population of approximate two-thousand magnificent frigatebirds that nest on the Galápagos Islands. Magnificent frigatebirds are currently classified as of Least Concern by the International Union for Conservation of Nature, but because of the genetic uniqueness of those on the Galápagos Islands this may need to be revisited.^[4]


This population on Cape Verde is thought to be extremely low and on the brink of extinction, despite the original sighting of this species by Columbus likely being that of the Cape Verde population. Protection of the frigatebird's breeding sites is necessary for the species' recovery.^[19]