The family Phaethontidae includes 3 species found in North America.

Tropicbirds occur in all tropical and subtropical oceans, spending their non-breeding time at sea, coming ashore only to breed. They are medium-sized (body 25-45 cm in length; weight 300-750 gms) aerial birds with a short neck, long, narrow wings and long central tail feathers extending 50-55 cm beyond the other feathers. The plumage is typically white, sometimes flushed with pink or orange and with a black bar across the eyes and black markings on the wings. The brightly colored yellow, red or orange bill is stout, pointed, slightly decurved with serrate tomia. The short legs are set far back and used for swimming; on land the birds cannot stand and must shuffle over the ground, pushing with the small feet. 

When foraging, tropicbirds fly several meters above the water, dropping in a swift nose-dive to capture flying-fish above the surface; other fish and squid are captured by plunge-diving from a height, usually with little penetration of the water but sometimes to a greater depth. Usually solitary, sometimes in pairs or small groups. When not breeding they remain at sea, resting on the water or flying.

Tropicbirds nest on islands, often in loose colonies on cliffs from which they can take off without walking. The nest is a scrape in sand or earth with little or no nesting material. They may also nest in cavities, caves, under overhanging rocks or under vegetation. On some Pacific islands they nest in trees. The single egg is pale to deep purple-brown with darker markings when laid, but the pigments are water soluble and are lost during incubation. Eggs are incubated by both sexes for 40-46 days. Hatchlings are covered with dense, silky, gray or yellowish-brown down. Young are fed by regurgitation into the throat of the young by both parents. Fledging is at 65-90 days, depending on food supply. Young become independent at fledging.