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| State Recognized | Indigenous |
| NatureServe Heritage Rank | G4/G5 – Apparently secure/Secure |
| North American Waterbird Conservation Plan |
Moderate concern |
| Regional Seabird Conservation Plan |
USFWS 2005 |
The Koa‘e ‘ula, also known as the Red-tailed Tropicbird, is a striking white seabird belonging to the family Phaethontidae, which includes boobies and frigatebirds. There are four recognized subspecies of Koa‘e ‘ula, and one of them (P. r. roseotincta) breeds in Hawai‘i.
Adult males and females are predominantly white, occasionally exhibiting a light pinkish tint. They have a partial black eye ring, a short eye line, black flanks, and black shafts on their outer primaries. Both sexes possess long, narrow tail feathers with red shafts. Their large, reddish-orange bill has a black tip, and they have very small legs and feet.
Their flight is characterized by strong flapping combined with gliding, allowing Koa‘e ‘ula to cover long distances effectively.
The Koa‘e ‘ula, also known as the Red-tailed Tropicbird, typically forages alone but may occasionally be seen with other species, often far from land. They are known to follow ships. These birds capture their prey by plunge diving. In Hawai‘i, their diet mainly consists of flying fish, but they also eat squid, mackerel scads, dolphinfish, truncated sunfish, and balloonfish.
Koa‘e ‘ula breed in colonies, and pairs usually remain together for many years. At the beginning of the breeding season, they engage in complex aerial displays. Nests are built on the ground and consist of a simple scrape lined with some vegetation. In Hawai‘i, breeding can occur year-round, but most nests are active from February to June. Each pair lays a single egg per season, and both parents share the responsibilities of incubating the egg, brooding, and feeding the chick. However, no care is provided after the chick fledges.
The Koa‘e ‘ula, also known as the Red-tailed Tropicbird, breeds throughout the Northwestern Hawaiian Islands (NWHI) and at a limited number of sites in the Main Hawaiian Islands (MHI), primarily on offshore islets. Breeding may also occur on Ni‘ihau, Ka‘ula, Lāna‘i, and Kaho‘olawe. Outside of Hawai‘i, the Koa‘e ‘ula breeds on oceanic islands in the Indian and Pacific Oceans. During the non-breeding season, adults are solitary and pelagic, and their range is not well documented.
The following management goals are essential to Pacific seabird conservation: maintain, protect, and enhance habitat; eradicate or control non-natives; minimize bycatch and other adverse effects of fishing; improve the effectiveness of oil spill response efforts; identify contaminants and hazardous substances; and minimize the impact of powerlines, towers, wind turbines, and lights (USFWS 2005). The goal of these management actions is not only to protect seabird populations and their breeding colonies, but also to re-establish former breeding colonies, thereby reducing the risk of extinction.
Introduced Predators: Like all seabirds, adults and their nests are vulnerable to predation by rats (Rattus spp.) and feral cats (Felis silvestris). Fortunately, all sites in the Northwestern Hawaiian Islands (NWHI) are free from both rats and cats.
Invasive Species: On Lisianski and Laysan Islands, rabbits (Oryctolagus cuniculus) have severely reduced suitable nesting locations by denuding the vegetation. Additionally, Golden Crown-beard (Verbesina encelioides) further degrades these crucial nesting habitats. At Kure, introduced Big-headed Ants (Pheidole megacephala) may contribute to nestling mortality and facilitate the destruction of native vegetation by supporting a non-native scale insect.
koaʻe
n. 1. The tropic or boatswain bird, particularly the white-tailed tropic bird (Phaethon lepturus dorotheae), which inhabits cliffs of the high islands. The red-tailed tropic bird (P. rubricauda rothschildi) is koaʻe ʻula; the white is koaʻe kea. Ka pali lele koaʻe, cliff [where] tropic birds fly. (PPN tawake.) 2. A variety of banana. (Neal 249.) Also aʻeaʻe and manini. 3. A taro; varieties are qualified by the colors ʻeleʻele, keʻokeʻo, ʻulaʻula. 4. A snapper, probably Etelis Coruscans, an important commercial fish also known as onaga (Japanese). 5. A variety of sweet potato.
A webinar related to the research of the Papahānaumokuākea Native Hawaiian Cultural Working Group tasked with giving Hawaiian names to numerous other bird, plant, limu, and coral species unique to PMNM
