Koa’e ‘Ula

One of three closely related species of seabird living in tropical oceans, The Red Tailed Red-Tailed-Tropicbird-1Tropicbird has almost all-white plumage with a black mask and a red bill. Most adults have red tail streamers that are about two times their body length, which gives rise to its common name.

There are many exotic birds that find their way to Hawai’i and stay. The Hawaiian honeycreeper, Nene, ‘Apapane and the Hawaiian stilt, to name just a few. All bring beautiful and striking color and many with their unique songs. Indigenous to the Hawaiian Islands, the Red Tailed Tropicbird nests in Hawai’i and other archipelago’s in the Pacific basin. They are also commonly found in tropical and subtropical areas of the Indian Ocean and around the world. Mature birds measure around 36 to 42 inches in length (including the streamers) and can have a wingspan of up to 44 inches.

The Red-Tailed Tropicbird’s are social and nest in large colonies on oceanic islands. 140621 1443 Red Tailed Tropicbird, Koa'e 'Ula (Phaethon rubricauda melanorhynchos)Common in Hawai’i, they are often found away from the main Hawaiian Islands, locations like Easter Island and across to Mauritius and the Reunion Island. In Madagascar they nest on the tiny island of Nosy Ve. In Australia, they nest on Queensland’s coral islands and islands off Western Australia.

This wayfaring bird disperses widely after breeding; birds fitted with leg rings in Hawai’i have been recovered as far away as Japan 140621 1464 Red Tailed Tropicbird, Koa'e 'Ula (Phaethon rubricauda melanorhynchos)and the Philippines. They range from the Red Sea to New Zealand and Chile. The breeding population in Hawai‘i is estimated between 9,000 and 12,000 pairs, with the largest populations on Midway Atoll and Laysan Island in the Northwest Hawaiian Islands.

Red Tailed Tropicbirds are solitary feeders, usually feeding during the day and rarely fish within sight of land. They dive, wings half-folded, into the water to catch their prey. Red-tails consume mostly fish (flying fish, mackerel, dolphinfish, balloonfish) and squid.

During mating, they perform complex aerial courtship displays. They are adept flyers, performing acrobatics in mating season which consist of flying backwards, vertical climbs and flying in complex circles. Birds begin breeding after 4 years of age and they nest year round with peak activity from March through August. Adults generally return to the same nest site each year, usually located in areas sheltered from the sun, at the base of a tree, in shrubs, or next to a structure.140621 1421 Red Tailed Tropicbird, Koa'e 'Ula (Phaethon rubricauda melanorhynchos)

The female lays a single egg, ranging in color from brown to purplish black. Relaying of another egg can occur if the first egg is lost or infertile. Both parents incubate the egg, a period that can last 39 to 51 days and because of their feeding habits, each adult parent averages incubation shifts ranging from 8-9 days.
During the first few weeks after hatching, chicks are attended and fed by one of its parents, both working in shifts similar to those during incubation. Nestlings are brooded almost continuously for the first week. Feeding takes place on an average of every 17 hours.
Chicks reach adult weight in six weeks. In 11 weeks, wing exercising begins and in 12-13 weeks, fledging occurs. Chicks fledge with a dark gray bill and white and gray plumage, which eventually gives way to the red beak, white plumage and the red streamers that give it its name.

Photos: Warren Iseke

Cover Photo: Nathan Yuen
PA Davis-photo card




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