Red-tailed Tropicbird – Koa’e Ula (Phaethon rubricauda)

- Life Span: > 15 years
- Size: 44–47 cm (17-19 in); 80-102 cm (31-40 in) with tail streamers
- Breeding Ecology:
- Breeds in tropical and subtropical areas of the Indian and Pacific oceans
- Complex aerial courtship displays
- 1 egg/clutch, may replace lost eggs
- Incubation lasts about 39-51 days
- Courtship displays include circular, reverse loops and rapid dives, often in groups of a half dozen or more.
- Midway hosts the largest nesting colony in the Hawaiian archipelago (5,000 nesting pairs).
- 12,000-14,000 breeding pairs in the Pacific ocean; 30,000-40,000 breeding pairs worldwide.
- Tropicbirds are “squawkers,” both on the ground and in the air, earning them the nickname of “bosun bird” for the call’s similarity to the boatswain’s whistle.
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White-tailed Tropicbird – Koa’e Kea (Phaethon lepturus)

- Life Span: > 15 years
- Size: 38-40 cm (15-16 in); 71-81 cm (28-32 in), including tail streamers
- Breeding Ecology:
- Nearly pantropical, being scarce only in the Eastern Tropical Pacific
- Commonly breeds on islands with steep cliffs or large trees (nests in tree cavities)
- 1 egg/clutch, may nest every 9-10 months
- Incubation lasts about 41 days, chicks fledge after 70 days post-hatching
- Rarely breeds on Midway Atoll NWR; 1-3 nests per year.
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