Brown Booby

‘A / Sula leucogaster
BRN booby
  • Speculated to be found at Kīlauea Point year round, though they are more likely to be seen March through September” 
  • Ā means to talk a lot or jabber in Hawaiian, which probably refers to the squawking noises the birds make. The chatter is especially noticeable from their colony at Kīlauea Point.
  • The adults are chocolate brown with white underwing coverts and belly. Sexes distinguishable by face, bill, and leg color. These parts are yellow in females and are grayish green in males, which in addition, have a bluish throat. Juveniles have plumage similar to adults except that their belly and under wing covert color is light brown. 
  • Frequently sighted fishing offshore and seen roosting along the Na Pali Coast, but it does not nest on Kaua‘i. In recent years, however, nesting sites have been observed on nearby islands. 
  • Boobies are pelagic birds. meaning they spend the majority of their life on the open ocean and only venture back to land to breed. Pelagic birds are powerful fliers with exceptionally long, thin wings. They can remain in flight for days or weeks, sleeping in-flight, while staying hundreds to thousands of miles offshore. They also have a special salt gland that helps them extract excess salt from their body. This allows them to drink seawater and ingest water from prey without accumulating toxic levels of salt in their bloodstream. 
  • They feed by plunging head first into the water from the air. Usually forages near shore, often within 80 km of breeding grounds. Solitary feeders and their primary prey item is flying fish. Feeding generally occurs during daylight hours.
  • Breeding season occurs between March and November. Breeds colonially. Nests are located on the ground and consist of a shallow depression surrounded by twigs or other vegetation. An average of two chalky white eggs are layed. Lacks brood patch and instead incubates with feet. Parents share incubation duties. Average incubation shift is 12 hours. Incubation period averages 43 days. The first egg hatches several days before the second. The first chick to hatch ejects the second chick from the nest shortly after it emerges from the egg, so generally only one chick survives. Chick feeding occurs on average once every 17 hours. Fledging occurs 85-103 days after hatching. Post-fledging care and feeding continues for 1-2months.

Facts About Brown Booby

Diet
Squid and fish, especially flying fish. 

Life Span
16 years

Size
Length: 64-85 cm (25.2.6-33.5 in); wingspan: 132-155 cm (52-61 in)