Red-Footed Booby

Sula sula

Like other members of the booby tribe, this bird can be found globally in tropical oceans. It is the smallest member of this clan and is the only polymorphic member of its genus. They range in color from an all brown bird to all white with black primaries and secondaries. Color morphs are not indicative of subspecies, and they can coexist, and even interbreed.

Unlike most members of the booby clan (genus Sula), the Red-Footed Booby prefers nesting in trees or shrubs. This strategy has benefited them by limiting the threat from ground-based predators. When these are not available, they may exploit clumps of grass to place their nest.

Flying fish and squid comprise the major portion of their diet. These birds are versatile foragers. Sometimes they employ steep vertical dives from about 20-25 feet. Most of their dives penetrate only a few feet below the surface. But they have been observed catching flying fish mid-flight, and feeding while floating near the surface. Evolution has provided boobies with special adaptations to accommodate their foraging style. One of which are the closed external nostrils, and secondary nostrils beside the mouth. They are covered by moveable flaps when the bird plunge-dives into the sea.

Taxonomists recognise three subspecies of Red-Footed Booby:

• S. s. sula breeds in the Caribbean and off the coast of eastern Brazil.
• S. s. rubripes breeds in the Indian Ocean, the tropical western and central Pacific Ocean, and east to Hawaii, Line Islands, the Marquesas and Pitcairn Island.
• S. s. websteri breeds in the eastern Pacific Ocean from the Revillagigedo Islands off southwestern Mexico, and south to the Galapagos Islands.

During the 2017 science expedition I participated in, we met Red-Footed Boobies at all four islands of the Archipiélago de Revillagigedo. However, they put on the best show as we pulled away from Isla Clarion to begin the long voyage home, on 2017-02-21. The exciting send-off remains as one of the many highlights lodged in my memories of the nineteen day voyage.