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Brown Booby

Sula leucogaster ORDER: SULIFORMES FAMILY: SULIDAE

IUCN Conservation Status: Least Concern

A widespread seabird of tropical waters, the Brown Booby ranges as far north as the Gulf of California, and rarely to both coasts of the United States. Like other boobies, it feeds with spectacular plunges into the sea.

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Appearance

Gull-like
Gull-like
Typical Voice

Adult Description

  • Large, dark waterbird.
  • Long body, long neck, long tail.
  • Narrow, pointed wings.
  • Brown head, throat, chest, and upperparts.
  • White belly, vent, and wing linings

Immature Description

Juvenile is brown overall; belly ranges from mottled brown and white to mostly dark. Sharp line still visible between darker chest and lighter belly. Underwing coverts are pale. Bare parts generally dull gray.

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Brown Booby Range Map
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Similar Species

  • Adult Brown Booby is easily distinguished from other adult boobies by its sharp border between dark brown chest and white belly.
  • Juvenile Masked Booby resembles adult Brown Booby, but has white lower neck and chest.
  • Red-footed Booby juvenile is also mostly brown, but its underwing coverts are all dark and upperwing shows white in wrist area when feathers are worn.
  • Immature Northern Gannet can have dark head and neck and paler chest, but the separation usually is not sharp. Gannet has feathering in front of eyes, boobies do not.