Great Frigatebird

‘Iwa / Fregata minor palmerstoni
Great Frigatebird
  • Found at Kīlauea Point year round
  • A large bird, with long, slender wings, a deeply forked tail and long, pale blue/gray to blackish hooked bill. Adults have mostly black plumage.
  • Adult males have a red inflatable throat pouch. Legs/feet red to reddish-brown. Scapular feathers have a purple-green sheen. In the breeding season, the male is able to distend its striking red gular sac.
  • Females have white breasts and on average are larger than males. Legs/feet pink to reddish-pink.
  • Juveniles have rusty to white heads and throats.
  • Why is the great frigatebird called ’iwa in Hawaiian? Well, ‘iwa means “thief” and although great frigatebirds capture most of their own prey, they are considered kleptoparasitic, meaning they steal food from other birds. Great frigatebirds harass their target mid-air by chasing them closely and pulling at tail feathers, causing their target to lose balance. They do this in hopes that their target, usually a red-footed booby, will regurgitate. If their target regurgitates, then the ‘iwa stops their chase and takes the food before their target falls into the sea. If you’d like to watch some kleptoparasitism in action, visit us in the afternoon when red-footed boobies are returning to their breeding colony and are more likely to be transporting food.
  • Great frigatebirds will make use of schools of predatory tuna or pods of dolphins that push schooling fish to the surface.
  • Like all frigatebirds they are usually incapable of taking off should they accidentally fall into the water.
  • ‘Iwa roost near Kīlauea Point but no nesting has been documented.
  • Frigatebirds are pelagic birds meaning they spend the majority of their life on the open ocean and only venture back to land to breed. Pelagic birds are powerful fliers with exceptionally long, thin wings. They can remain in flight for days or weeks, sleeping in-flight, while staying hundreds to thousands of miles offshore. They also have a special salt gland that helps them extract excess salt from their body. This allows them to drink seawater and ingest water from prey without accumulating toxic levels of salt in their bloodstream.
  • ‘Iwa begin to breed after 9 years. Females do not breed every year because it takes a year and a half to raise a chick. Males are believed to breed every year (with a second female). Fidelity to nest sites and mates is low.
  • Male breeding displays include inflation of crimson throat pouch, spread wings and head shaking. A single egg is laid on a platform nest built on top of shrubs. Both parents develop a brood patch and incubate the egg for about 55 days. Incubation shift change averages every 3 days.
  • Newly hatched chicks are naked and brooded by parents to protect them from the sun or rain. By one month, both parents leave the nest to search for food. Feedings occur about once every 18 hours. Chicks attempt their first flight between 120-145 days. Young will depend on parents, usually the female, for food for up to 18 months after fledging.

Facts About Great Frigatebird

Diet
Lacking the ability to take off from water, frigatebirds snatch prey from the ocean surface using their long, hooked bills. Prey primarily consists of fish and squid. Juveniles and adults often obtain food by piracy from boobies, tropicbirds, and shearwaters. Frigatebirds often supplement their diet by this type of harassment.

Life Span
30 years

Size
Length: 86-100 cm (34-40 in); wingspan: 206-230 cm (81-91 in)