The family Fregatidae includes 3 species found in North America.

Frigatebirds occur on all tropical and subtropical seas and islands. They are 70-110 cm in length with long, narrow wings (over 2 m in largest species), a deeply forked tail, short legs, small feet and a long, hooked bill. Females are larger than males. Males are glossy black, sometimes with white ventral patches; females mainly white below. Eye ring, throat skin and feet often brightly colored. Gular skin (pouch below bill) is bare and inflatable like a red balloon in breeding males. Immatures have white heads. They are remarkable flyers, spending most of the time on the wing except when breeding. 

Food is mainly flying fish and squid often taken from boobies and terns by piracy, i.e., by harassing the victim until it disgorges fish it is carrying, which the pirate then catches in midair. Frigatebirds fly above shoals of tuna and dolphins to catch flying fish that leap out of the water to escape the predators, pick up dead or dying fish, baby sea turtles and offal from the beach or surface of the water, or swoop low over breeding colonies of seabirds to snatch unattended nestlings, including those of their own species.

They nest in colonies in trees or low shrubs, rarely on the ground. Nests are built of sticks, feathers, bones, etc., assembled mainly by male, built mainly by female during courtship and incubation. There is much theft of nest material among neighbors. Clutch 1 large, white egg. Both parents incubate 44-55 days. Naked hatchlings are brooded for 2 weeks until covered with pale gray down. Young cared for and fed by both parents by incomplete regurgitation, i.e., young feeds from throat or beak of adult. Young guarded by adults for up to 45 days. Fledging delayed up to 6-7 months, plus long period of post-fledging care for 4-10 months or longer. During this period the young birds gather in small groups, picking up objects from the surface of the sea, attacking boobies and terns and taking small chicks, including unattended frigatebirds.