The name ‘booby’ comes from the Spanish word bobo, meaning ‘fool’ or ‘dunce’, referring to the clumsiness of boobies on land (9). However, in the air the blue-footed booby is a strong and agile flier (5) (8) (9), foraging by plunge-diving into water, often from a considerable height (3) (8) (9). A social species, it often forages in groups of up to 200 birds (2) (7) (8), mainly taking fish such as sardines, anchovies and mackerel, as well as some squid (2) (4) (5). It has also been reported to take flying-fish (Exocoetus) from the air (2) (3).
The blue-footed booby usually nests in colonies of up to several hundred, although pairs may also nest alone (5). Breeding may be seasonal in some areas, but occurs opportunistically in others (2). Boobies usually mate for life (9), and perform an elaborate and somewhat comical courtship display that involves the male ‘skypointing’ (pointing the head and beak upwards and spreading the wings), alternately lifting each blue foot, with the tail held cocked, and often emitting a whistling call. Both members of the pair may then skypoint, touch beaks, lift the feet, or pick up twigs or stones and place them on the ground (9) (10). The nest is built on bare ground, within a circle formed from accumulated guano (2) (3). One to three eggs are laid (2) (3), hatching after an incubation period of around 41 days (2). Interestingly, boobies does not have a brood patch, but incubate the eggs using heat supplied from a rich network of blood vessels in the webs of the feet (9). Unlike some other booby species, the blue-footed booby does not show obligate brood reduction (where one or more of the chicks are always lost) (2) (5), but if food becomes limiting the eldest chick may exclude younger chicks, which may then starve (5). Surviving chicks fledge after around 102 days, and are dependent on the adults for a further 56 days. Breeding may occur from two to three years old (2).