Masked Booby – ‘A (Sula dactylatra)
- Life Span: > 20 years
- Wingspan: 152 cm (62 in)
- Breeding Ecology
- Breeds in Main and Northwestern Hawaiian Islands, and throughout tropical regions of Pacific, Atlantic, and Indian Oceans
- 2 eggs/clutch (only 1 chick survives); 1 clutch/year (replacement laying occurs)
- Masked Boobies nest in small numbers at Midway; historical data suggest they were never particularly numerous; generally fewer than five nesting attempts per year
- Boobies lack a brood patch and incubate with their feet.
- Learn more
Brown Booby – ‘A (Sula leucogaster)
- Life Span: > 20 years
- Wingspan: 132-155 cm (52-61 in)
- Breeding Ecology:
- Pantropical breeding range
- 2 eggs/clutch (only 1 chick survives); 1 clutch/year (replacement laying occurs)
- Incubation lasts 42-45 days; chicks fledge after 100 days
- Populations worldwide have declined dramatically over the past 200 years and may be at only 10% of historic levels.
- Brown Boobies were the most common booby species at Midway in the 1930s but declined quickly with the introduction of rats (Rattus rattus).
- Learn more
Red-footed Booby – ‘A (Sula sula)
- Life Span: > 20 years
- Wingspan: 91-101 cm (36-40 in); smallest of the boobies
- Breeding Ecology:
- Breeds throughout Pacific, Atlantic, Caribbean, and Indian Oceans
- Colonial tree nester in association with Great Frigatebirds
- Only booby to nest almost exclusively in shrubs and trees
- Male brings sticks to the female for nest site construction
- 1 egg/clutch; 1 clutch/year
- Incubation lasts about 45 days; chicks fledge after 95-100 days
- Learn more
Great Frigatebird – ‘Iwa (Fregata minor)
- Life Span: > 25 years
- Wingspan: 206-230 cm (81-91 in)
- Breeding Ecology:
- Male “lek” display
- Pantropical breeding range
- Colonial tree nester
- 1 egg/clutch; 1 clutch/1.5 years
- Up to 450 days before fledging
- Lacks ability to take off from water.
- Obtains some food by piracy from other birds.
- Highly specialized for an aerial life, having a greater ratio of wing area to body mass than any other bird, a deeply forked tail for agile maneuvering, and very small legs and feet (which make walking impractical).
- The Hawaiian name for the species “‘Iwa” means “thief.” But frigatebirds catch the majority of their meals without stealing. They fly along the ocean waiting for a flying fish to break the surface, or catch fish and squid swimming within several centimeters below the surface.
- Females do not breed every year because it takes 1½ years to raise a chick. Males are believed to breed every year (with a second female). Fidelity to nest sites and mates is low.
- Learn more
