Structure of Masked Booby
Masked Booby breeds on islands in tropical oceans, except in the eastern Atlantic; in the eastern Pacific it is replaced by the Nazca booby, Sula granti, which was formerly regarded as a subspecies of masked booby. It is also called the masked gannet or the blue-faced booby. The adults of Masked Booby are white with pointed black wings, a pointed black tail, and a dark grey facemask.
Sexes of Masked Booby
The sexes of Masked Booby are similar. But the male Masked booby has a yellow bill, and the female's is greenish yellow; during the breeding season they have a patch of bare, bluish skin at the base of the bill. Juveniles are brownish on the head and upperparts, with a whitish rump and neck collar. The under parts are white. The adult plumage of Masked Booby is acquired over two years.
Colours of Masked Booby
Masked Booby is like a conspicuous and distinct gannet-like species. It was proposed for separation to a monotypic subgenus Pseudosula, but the Nazca booby and as it seems also the brown booby (S. leucogaster) are quite close relatives.
Coining of Masked Booby
Masked booby was first described by French naturalist Rene-Primevere Lesson in 1831. The masked booby is one of six species of booby in the genus Sula. The Nazca booby (S. granti) was formerly regarded as a subspecies.
Breeding of Masked Booby
Masked booby breeds in the central and western Pacific Ocean and around Australia, as well as off Mexico and on Clipperton Island. Some of the birds migrated towards tropical countries like Indian Ocean and the Bay of Bengal Coastal lines.
Behaviour of Masked Booby
Masked booby is s spectacular diver, plunging diagonally into the ocean at high speed. They mainly eat small fish, including flying fish. This is a fairly sedentary bird, wintering at sea, but rarely seen far away from the breeding colonies. However, Caribbean birds occasionally wander north to warm southern Gulf Stream waters off the eastern seaboard of the United States. More remarkably, there have been three western Palaearctic records of masked booby, presumably dactylatra, all from Spanish waters, although one of these also entered French territorial areas.
Nests of Masked Booby
Masked booby nests in small colonies, laying two chalky white eggs on sandy beaches in shallow depressions, which are incubated by both adults for 45 days. In most cases, the first chick will kill its smaller, weaker sibling after it hatches. Siblicide has been well studied in this species; researchers such as David Anderson have demonstrated that while the boobies can manage to feed two chicks if siblicide is prevented, they do so at a steep penalty to health and future reproductive success.
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