Birds of Midway Atoll

White-tailed Tropicbird / Phaethon lepturus dorotheae

Description Adult birds have mostly white plumage with long, white, tail streamers (33-40 cm). Tail feathers are visible while the bird is in flight as compared to the Red-tailed Tropicbird. Black eye-stripe from gape curving towards and passing through eye. Diagonal black stripe across upperwings. Yellowish to orange bill. Legs/feet are yellowish with black webs. Length: 38-40 cm (15-16 in), 71-81 cm (28-32 in) including tail streamers; wingspan: 89-94 cm (35-38 in); average life span: 16 years.

White-tailed Tropicbird Photo credit: Robert Shallenberger

Midway Population

In 2006, six known breeding pairs nested on Sand Island. Constant monitoring aids in accurate counts and identification of nesting sites which are difficult to locate because of their scattered distribution.

Feeding Habits

Typically solitary feeders though sometimes seen in pairs. With folded wings, white-tails hit the water and completely submerge to seize and swallow prey before flight. Prey consists of fish and squid.

Breeding

Courting birds fly in parallel, with streamers from bird above turned downward toward mate. Fly together in shallow glides. Begin nesting at four years of age.

Nest year round with peak activity from March through October. Primarily a cliff or cavity nester. On Midway, birds nest in cavities of tree limbs, root bases of ironwood trees (Casuarina equisetfolia) and/or other secluded spots. A single egg is laid and incubated (40-42 days) by both adults. Lacks brood patch. Average incubation shift lengths range from about 4-8 days. Chicks are tightly brooded for the few days after hatching. Unlike other Pelicaniformes, adults regurgitate food by putting their bills down the gaping chick's throat. Average chick fledge times vary between 10-12 weeks.