Great Frigatebird Fact File
The great frigatebird has a body covered almost entirely with black feathers for males. Females have a white patch on the breast and throat while males have red on their chin. This red patch in males is the gular sac which is inflated by males during the breeding season.
Their wings are angles and long. Their bill is long and has a hook at the end to help catch fish. It is colored bluish-black. The tail feathers are deeply forked. This tail serves as a rudder when flying.
These birds are incredibly light helping them to fly. Their bones only account for around 5% of their body weight. An average weight for a great frigatebird is between 1 and 1.5kg (2.25-3.25lbs).
An average great frigatebird will measure 85-100cm (2.8-3.3ft) long with a wingspan of 2-2.3m (6.6-7.5ft) across.
The great frigatebird is a carnivore. Their diet includes fish, squid, the chicks and eggs of seabirds and carrion (dead animals).
Great frigatebirds may steal food from other birds such as boobies by chasing them until they regurgitate their food.
To obtain food they will fly close to the surface of the water and then dip their bill in to grab fish. As their feathers are not waterproof they will raise the wings to ensure they do not get wet.
These ocean going birds can be found on the coastlines of a number of countries. They are typically found in the Indian, Pacific and south Atlantic oceans with vagrant populations showing up outside of these areas.
A full list of the countries in which they have been recorded is provided here: American Samoa, Aruba, Ascension and Tristan da Cunha, Australia, Brazil, British Indian Ocean Territory, Brunei Darussalam, Cambodia, Chile, China, Christmas Island, Cocos (Keeling) Islands, Colombia, Comoros, Cook Islands, Costa Rica, Ecuador Ecuador, El Salvador, Fiji, French Polynesia, French Southern Territories, Guam, Guatemala, Kiribati, India, Indonesia, Japan, Kenya, Madagascar, Malaysia, Maldives, Marshall Islands, Mauritius, Mayotte, Mexico, Micronesia, Mozambique, Nauru, New Caledonia, New Zealand, Nicaragua, Niue, Northern Mariana Islands, Oman, Palau, Panama, Papua New Guinea, Philippines, Pitcairn, Réunion, Saint Helena, Samoa, Seychelles, Solomon Islands, Somalia, South Africa, Sri Lanka, Taiwan, Tanzania, Thailand, Timor-Leste, Tokelau, Tuvalu, United States Minor Outlying Islands, Tonga, United States, Vanuatu, Viet Nam, Wallis and Futuna and Zimbabwe.
Breeding takes place on small islands which are mostly tropical or sub-tropical. They will nest among mangroves or on bare ground. Most of their time is spent hovering over the sea.
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Breeding season is highly dependent on their location taking place anytime from December to September depending on where they live.
The great frigatebird breeds on small islands which are tropical or subtropical. These nests are created in mangroves or on bare ground. The nest is formed from twigs and sticks with males often building this is the same tree where they performed their courtship display. They often nest alongside other bird species.
To attract a mate the male will inflate his large throat sac. While considered monogamous pairs will ‘divorce’ if they are not successful in mating together. It is also not uncommon for males to try and mate with females when their mate is away.
A pair will work together to incubate the egg for the 55 day incubation period. Typically only a single egg is produced every two years by the female.
The nestlings are reliant on the parents to shield them from the heat.
It takes 140 to 168 days for the chick to fledge. They may remain with parents for over a year receiving food and protection.
Sexual maturity is not reached till between five and seven years old.
While they receive a large amount of parental care many birds perish within the first few months of becoming independent.
They are generally silent but when in flight they may create a warble and they whistle when coming in to land.
In flight they hold this wings in an ‘M’ shape. This increases their maneuverability but does lead to a reduction in stability. The wings are narrow allowing them to fly for hours at time without much effort being required. They will often fly together in large groups.
It is thought they remain in the air for months at a time and can sleep while in the air. Some may roost in a tree over night.
They cannot swim due to their feathers not being waterproof and are also unable to walk on land.
Predators and Threats
Adults have no natural predators except for humans. Eggs and chicks are taken by owls, rats, curlews and domestic cats.
Their feathers were used by the Polynesians in cloaks and feathered staffs for the elite members of their tribe.
Human disturbance may lead parents to abandon their nest site. Climate change is likely to impact this species as they nest on islands.
Great frigatebirds have the largest wing area to body mass ratio of any bird.
They are also known as the pirate bird, sea hawk or ‘man-o-war’ bird.
In Hawai’ian they are known as the ‘iwa,’ which means thief.
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Burnie, D., 2011. Animal. 3rd ed. London: DK
Ambrose, J., 2015. Wildlife Of The World. 1st ed. London: Dorling Kindersley, p.
Morcombe, M., 2003. Field Guide To Australian Birds. Archerfield, Qld.: Steve Parish Pub.
Galbraith, M.P. 2013 [updated 2017]. Great frigatebird. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz
Dewey, T. 2009. “Fregata minor” (On-line), Animal Diversity Web. Accessed November 17, 2020 at https://animaldiversity.org/accounts/Fregata_minor/
American Bird Conservancy. 2020. Great Frigatebird (‘Iwa) | American Bird Conservancy. [online] Available at: <https://abcbirds.org/bird/great-frigatebird/> [Accessed 17 November 2020].
Fws.gov. 2020. Great Frigatebird – Hawaiian Islands – U.S. Fish And Wildlife Service. [online] Available at: <https://www.fws.gov/refuge/hawaiian_islands/wildlife_and_habitat/great_frigatebird.html> [Accessed 17 November 2020].
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