Measurements
Both Sexes
- Length
- 25.2–33.5 in
64–85 cm - Wingspan
- 52–61 in
132–155 cm - Weight
- 33.5–63.5 oz
950–1800 g
Other Names
- White-bellied Booby
- Fou brun (French)
- Boba prieta, Bubi chaleco (Spanish)
Cool Facts
- The Brown Booby is the only ground-nesting booby that regularly builds a substantial nest.
- Like all boobies and pelicans, the Brown Booby's feet are "totipalmate," having webbing connecting all four toes.
- Brown Booby nests sometimes contain the bodies of dead Sooty Tern chicks.
- Male and female Brown Boobies generally look alike in plumage color, except in populations found along the Pacific Coast of Mexico and Central and South America. There the females look like those in other populations, but the males have light gray to white heads.
Habitat
Ocean
Nests on islands, covering a wide range of vegetation types, geologic features, and weather patterns. Found at sea in nonbreeding season.
Food
Fish
Squid and fish, especially flying fish.
Nesting
Nesting Facts
- Clutch Size
- 1–3 eggs
- Egg Description
- Pale bluish or greenish, with white outer layer.
- Condition at Hatching
- Blind and helpless.
Nest Description
Mound of branches, bones, grass, human-generated trash, or other items. Placed on flat ground, usually in full sunshine. Nests in colonies.
Nest Placement
Ground
Behavior
Aerial Dive
Plunge-dives from various heights up to 15 m (50 feet). Folds wings next to body at beginning of dive, then thrusts wings straight out over back, touching in the middle, just before breaking the surface. Dive may reach just below surface, or to as much as 2 m (6 feet) deep. Commonly feeds in areas where large predatory fish such as tuna drive smaller fish to the surface. Also follows fishing vessels.
Conservation
Least Concern
No longer breeds on many tropical islands where predators have been introduced. Human population growth and development of islands have caused severe population declines over the past century in the Caribbean.
Credits
- Schreiber, E. A., and R. L. Norton. 2002. Brown Booby (Sula leucogaster). In The Birds of North America, No. 649 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.