White-tailed Tropicbird

Koa‘e ‘ula / Phaethon lepturus dorotheae
White-tailed tropicbird

 

  • Found February - October
  • In Hawaiian koa‘e refers to tropic birds while kea means white
  • Adult birds have mostly white plumage with long, white tail streamers. Tail feathers are visible while the bird is in flight as compared to the koa‘e ‘ula. Black eye-stripe from gape curving toward and passing through the eye. Diagonal black stripe across upper wings. Yellowish to orange bill. Legs/feet are yellowish with black webs.
  • Typically solitary feeders though sometimes seen in pairs. With folded wings, koa‘e kea dive into the water and completely submerge to seize and swallow prey before flight.
  • In the US, this bird is mostly seen on Kaua’i where they nest along steep cliffs and inland mountain valleys. Though this species is widespread throughout the world, the population is in decline in Hawaii due to habitat loss, introduced species such as cats, fishing hooks and nets, and plastic marine debris which can entangle them.
  • Tropicbirds 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.
  • Courting birds fly in parallel, with streamers from bird above turned downward toward mate. Fly together in shallow glides. Begin nesting at 4 years of age. Nesting habitat is coastal cliffs, primarily in a scratched out hollow with a cliff crevice. Nest year round with peak activity from March through October. At Kīlauea Point, birds nest in cavities of tree limbs, root bases of ironwood trees 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 Pelican relatives, adults regurgitate food by putting their bills down the gaping chick's throat. Average chick fledge times vary between 10-12 weeks.

Facts About White-tailed Tropicbird

Diet
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.

Life Span
16 years

Size
Length: 38-40 cm (15-16 in), 71-81 cm (28-32 in) including tail streamers; wingspan: 89-94 cm (35-38 in)