Red-footed booby
A tropical seabird with red feet and varied plumage.
The red-footed booby (*Sula sula*) is a large seabird and the smallest member of the booby and gannet family. Adults always have red feet, but their plumage comes in several color forms, or morphs. These birds are powerful and agile in the air, using the wind to fly efficiently, but they are clumsy when taking off and landing. They hunt by snatching flying fish from above the ocean’s surface and by making shallow dives. Found across the tropics, they breed in large colonies along coasts, especially on remote islands like St. Brandon, Mauritius, and the Chagos Archipelago. Though their population is declining, the International Union for Conservation of Nature lists them as a species of least concern. They face threats from climate change, competition with fisheries, human disturbance, and invasive species.
The species was first described by Carl Linnaeus in 1766, who named it *Pelecanus sula* based on a specimen from Barbados. The current genus, *Sula*, was introduced by Mathurin Jacques Brisson in 1760; the word *Sula* is Norwegian for a gannet. Three subspecies are recognized: *S. s. sula* in the Caribbean and southwest Atlantic islands; *S. s. rubripes* in the tropical Pacific and Indian Oceans; and *S. s. websteri* in the eastern central Pacific.
Adults measure about 70 cm (28 in) long with a wingspan up to 152 cm (60 in). The average weight of 490 adults from Christmas Island was 837 g (1.845 lb). Their legs are red, and their bill and throat pouch are pink and blue. Plumage varies: the white morph is mostly white with black flight feathers; the black-tailed white morph looks similar but has a black tail, which can cause confusion with Nazca and masked boobies. The brown morph is entirely brown, while the white-tailed brown morph has a white belly, rump, and tail. The white-headed and white-tailed brown morph has a mostly white body, tail, and head, with brown wings and back. Different morphs often breed together, though one or two morphs dominate in most regions—for instance, in the Galápagos Islands, most are brown morphs, though white morphs also occur. Males and females look alike. Juveniles are brownish with darker wings and pale pinkish legs; chicks are covered in dense white down.
The red-footed booby is widespread across the tropics of the Atlantic, Pacific, and Indian Oceans. In the Atlantic, they mainly live in the Caribbean islands. In the
- Scientific name
- Sula sula
- Family
- Sulidae
- Length
- about 70 cm (28 in)
- Wingspan
- up to 152 cm (60 in)
- Average weight
- 837 g (1.845 lb)
- IUCN status
- Least concern (population declining)
- Number of subspecies
- 3
Lore & Background
The red-footed booby was formally described by Carl Linnaeus in 1766 in the twelfth edition of his Systema Naturae, under the binomial name Pelecanus sula. The present genus Sula was introduced by Mathurin Jacques Brisson in 1760. Three subspecies are recognized: S. s. sula, S. s. rubripes, and S. s. websteri.
This species breeds on islands in most tropical oceans. It nests in large colonies, laying one chalky blue egg in a stick nest, incubated by both adults for 44–46 days. Pairs may remain together over several seasons and perform elaborate greeting rituals. The diet consists mostly of fish and squid, caught by diving vertically from heights of 4 to 8 m or by catching flying fish in the air.
Adult red-footed boobies are hunted by coconut crabs, which use their claws to break the birds' wings or catch them by the legs. Nestlings and eggs are attacked by rats, cats, pigs, raptors, and Micronesian starlings. Humans also eat both adults and nestlings. The species has been extirpated from several islands due to introduced predators and human predation.
Reader's Guide
The red-footed booby is significant as a widespread tropical seabird that demonstrates remarkable variation in plumage morphs, including white, brown, and intermediate forms. Its breeding biology—colonial nesting in trees or bushes, long incubation and fledging periods—reflects adaptations to remote island environments. The species faces threats from climate change, competition with fisheries, human disturbance, and invasive species. Although its population is declining, the IUCN considers it a least-concern species. The red-footed booby's ability to travel hundreds of kilometers from land while foraging and its vulnerability to introduced predators highlight the delicate balance of island ecosystems. Its presence as a vagrant in regions such as the United States, Canada, Sri Lanka, New Zealand, and the United Kingdom indicates its wide-ranging movements. The species also serves as a case study in the impacts of El Niño events, as seen on Christmas Island where breeding was severely reduced during the 1982–1983 warm phase.
Did You Know?
- The red-footed booby is the smallest member of the booby and gannet family, with a length of about 70 cm and a wingspan up to 152 cm.
- Adult red-footed boobies are known to be hunted by coconut crabs, which break their wings or catch them by the legs.
- The species has three subspecies: S. s. sula, S. s. rubripes, and S. s. websteri.
- On Christmas Island, the 1982–1983 El Niño reduced breeding from about 6000 pairs to only 30 pairs in 1982 and around 60 pairs in 1983.
More in Birds of the Indian Ocean 1-24
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