Skip Navigation

Masked Booby

Sula dactylatra / Fua'o
Masked boobies
Largest of the tropical boobies nesting at Rose, adult birds are white with dark brown or black flight and tail feathers. Bill color is yellow and feet are yellowish gray. Facial skin is gray-black. Sexes are similar in appearance except that the females are larger in size. Males and females can be distinguished by their voices with the female giving loud honks and the males doing a whistling call. Juveniles are generally grayish brown with white underside. Adult plumage is attained by the third year.

Masked boobies nest on the ground and consist simply of a shallow depression. They begin breeding at four years of age and are monogamous. Two chalky white eggs are laid. They lack a brood patch and instead incubate with their feet. Parents share incubation duties. The incubation period averages 43 days and the first egg hatches four to nine days before the second and the first chick to hatch ejects the second chick from the nest shortly after it emerges from the egg. Chick feeding occurs once or twice a day. Fledging occurs 109-151 days after hatching. Post fledging care and feeding continues for one to two months. 

Facts About Masked Booby

Diet
Feeds by plunging head first into the water from the air, sometimes diving from as high as 30 m. Feeding areas are usually many miles from land and feeds primarily on fish and squid. Feeding generally occurs during daylight hours.
Life Span
20 years
Size
Length: 74-86 cm (29-34 in); wingspan: 152 cm (62 in)
Page Photo Credits — Jared Underwood/USFWS
Last Updated: Feb 11, 2014
Return to main navigation