Masked Booby

Sula dactylatra

These birds can be found in tropical oceans in most places of the world. The Masked Booby is the largest of all birds in the booby clan.

Until recently, the Nazca Booby was regarded as a subspecies of the Masked Booby. However, in 2000, enough evidence was accumulated to show they belonged to their own species.

Boobies nest in large colonies, often with only a few meters of separation. They lay one or two large eggs when nesting, but typically, only one chick ever survives. When these birds forage, they make spectacular high-speed plunge dives into the water after small fish are often driven to the surface by schooling dolphin or tuna.

Today’s taxonomists recognize five subspecies of Masked Booby:

• S. d. dactylatra breeds on islands in the Caribbean and off the northern coast of South America.
• S. d. melanops lives in the Red Sea and the western Indian Ocean.
• S. d. personata breeds in the southeastern Indian Ocean.
• S. d. tasmani breeds in the northern Tasman Sea.
• S. d. bedouti lives in the eastern Indian Ocean. Some researchers deny this subspecies and consider it a member of S.d. personata.

Masked Boobies sometimes show up in San Diego waters, and sometimes these are birds in poor health. It was my good fortune to meet them on the 2017 science expedition I attended to the Revillagigedo Islands, especially on Isla San Benedicto, a small island whose volcano erupted in 1952, extinguishing all life from its surface.