Midway Population

About 95 pairs nest on Eastern Island (1998). Great Frigatebirds range widely within tropical Indian and Pacific Oceans.

Feeding Habits

Lacking the ability to take off from water, frigatebirds snatch prey from the ocean surface using their long, hooked bills. Prey primarily consist 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.

Breeding

Frigatebirds begin to breed after nine 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 (naupaka [Scaevola sericea] and tree heliotrope [Tournefortia argentea]). Both parents develop a brood patch and incubate the egg for about 55 days. Incubation shift change averages every three 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.