Brown BoobySula leucogaster

adult male
Robert L. Pitman/VIREO
adult female
Rick and Nora Bowers/VIREO
adult female
Rick and Nora Bowers/VIREO
juvenile
John Cancalosi/VIREO
adult male
Robert L. Pitman/VIREO
adult female
Doug Wechsler/VIREO
Brown Booby
Brown Booby

Description

30" (76 cm). Adult has dark brown head, upperparts, and breast, with sharply contrasting white belly and white underwing coverts. Immature is gray-brown above and below; darker on head, wings, and tail.

Voice

Usually silent, but gives a variety of quacking, grunting, and screeching calls on the breeding grounds.

Listen

social calls

Habitat

Tropical and subtropical seas; breeds on coastal islands.

Range

Worldwide in tropical seas. Summer visitor to Gulf Coast and Caribbean Sea; casually farther north in western Atlantic; occasionally seen in southern California's Salton Sea; accidental along Pacific Coast.

Discussion

Of the boobies seen off the beaches of the Gulf of Mexico, this species is by far the most plentiful. Like the Northern Gannet, they dive for fish by plunging into the sea, but they also skim the surface to catch flying fish that leap clear of the surf. Frigatebirds often harass boobies, chasing them and forcing them to disgorge their prey, which the agile frigatebird then catches in midair. When on the wing, but not fishing, boobies often flap and glide in lines close to the surface of the waves and may resemble shearwaters. On land, these birds are dependent on a strong wind for takeoff from a tree or other elevated perch. On calm days they rest in vegetation or on the ground.

Nesting

1-3 pale blue or green eggs on bare ground in a slight mound of broken shells and scattered vegetation, usually at the edge of a cliff.

Similar Species

adult

Northern Gannet

35-40" (89-102 cm). Adult white with black wing tips; head tinged with orange-buff. Long pointed tail and wings. Immature dark gray, variously speckled and patterned with white, depending on age.

adult

Masked Booby

32" (81 cm). A stocky white seabird with black tail, black tips and trailing edges to the wings, and stout pinkish or orange bill.

adult male and female

Blue-footed Booby

32-34" (81-86 cm). Large seabird with long pointed bill, wings, and tail. Head and neck pale, streaked brown. Wings, back, and tail dark brown; white patches on nape and rump; underparts white.

adult, brown morph

Red-footed Booby

26-30" (66-77 cm). W. 36-40" (91-101 cm). Smallest of the sulids. Plumage highly variable.

Vireo

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