Red-footed Booby Life History

Habitat

Red-footed Boobies nest on tropical atolls and islands, usually with trees, but may use clumps of grass or human-made structures for nesting. Nonbreeding birds live in tropical ocean waters. Adults often remain year-round near the nesting area, whereas younger, nonbreeding birds (juveniles and subadults) may disperse farther away. At sea the birds roam in search of prey over vast areas of ocean. Large-scale changes in ocean currents, such as during El Niño events, influence the distribution of Red-footed Boobies and other seabirds.

Food

Red-footed Boobies prey on fish and squid, which they hunt by flying slowly above the ocean. Once they spot prey, they swiftly plunge-dive to capture them with the bill, often immersing themselves completely. This species, slimmer and more agile than larger boobies, takes much of its prey without diving. Individuals may ride on a ship, or fly alongside it, and when flying fish take to the air in front of the vessel, the booby flies swiftly toward it, catching it in the bill. Red-footed Boobies also congregate around actively feeding fish such as tuna, which drive small fish toward the surface. Once they have captured prey, they swallow it immediately. Their prey species are little-known but include snake mackerels, flying fish, and small squid.

Nesting

Nest Placement

Nests are usually set in a seaside tree such as fig, mangrove, screw palm, cordia, beach naupaka, or beach heliotrope, but some nests are constructed inland, several miles from the sea. On coral atolls or islands with no trees, nests are placed on grass or even cement blocks.

Nest Description

Tree nests are roughly circular in shape and set in the crown of the tree. They are constructed of twigs. The female often lines the bowl with grasses or leaves. Ground nests are much simpler, with few twigs or vegetation added. Tree nests measure about 12 inches across and 4.5 inches tall, with an inner depression 5.8 inches across and 3.1 inches deep.

Nesting Facts

Behavior

Much like other boobies, Red-footed Boobies perform elaborate, stylized courting displays. Males slowly circle over the site they have chosen, fly out toward the sea and then return to land in a tree with their feet on full display. They don’t show them off by parading, as some boobies do; they tend to hop for maximum effect. On landing, the males give a loud, harsh “landing call,” point the bill and tail skyward, open the wings halfway, and call out to passing females—a display called “sky-pointing.” An interested female will land next to the displaying male, and the two will look downward and shake their heads rapidly, stretch their necks upward with bill held horizontally, bow to each other, and together perform the sky-pointing display. Red-footed Boobies are socially monogamous and may keep a partner for 10 years or more. They often return to the previous season’s nest site. Pairs maintain their bond with repeated displays through the breeding season and by preening each other’s heads and necks. In colonies, nest sites are usually spaced 3–6 feet apart.

Both adults participate in ritualized nest building. The male brings most of the twigs and the female places them on the nest. As they call, display, and place the twigs with care, they often wave a stick from side to side in the bill before placing it. Once the nest is complete, one adult stays at the nest to keep other boobies and frigatebirds from stealing their twigs, even before an egg is laid. Red-footed Boobies defend their nest site against other birds, including frigatebirds, tropicbirds, and other boobies. They threaten with head shaking, bill pointing, flapping, and calling. Both male and female incubate the eggs and feed the chicks. After fledging, the juveniles go to sea to forage among flocks of their species, and some disperse far from their natal areas. At most active nesting colonies, younger birds (juveniles and subadults) are present, roosting near older nesting birds.

Conservation

Red-footed Booby populations appear to be declining in most parts of the species’ range. Partners in Flight estimates the global breeding population at 1.4 million birds and rates the species a 12 out of 20 on the Continental Concern Score, indicating a species of relatively low conservation concern. Humans continue to hunt the species for food and take its eggs, and sport-shooting is a problem in some colonies. In other places, loss of coastal habitats to erosion and development continues to reduce areas available for nesting.

Credits

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA.

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Schreiber, Elizabeth A., R. W. Schreiber and G. A. Schenk. (1996). Red-footed Booby (Sula sula), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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