Blue-footed booby Sula nebouxii

Identification Tips:

• Length: 26 inches Wingspan: 64 inches
• Sexes similar
• Pelagic bird only coming ashore to breed
• Large bird that dives for fish from air
• Takes 2 to 3 years to reach adult plumage

Adult

• Pale, streaked head
• Dark mantle with white patches on nape and rump
• White underparts
• Dark tail sometimes with white patch
• Large, dark, pointed bill
• Blue legs and feet

Immature

• Plumage similar to adult
• Underparts white with straight line between breast and belly

Similar species:

At close range, the blue legs and feet are diagnostic. Immature boobies of other species are very similar to Blue-footed Boobies. Brown and Red-footed boobies have darker bellies. Masked Booby lacks the pale rump patch and has a more U-shaped demarcation between the dark upper breast and the white belly. Northern Gannets tend to lack the white patches on the nape and rump but at a distance may be inseparable.

Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.