The blue-footed booby (Sula nebouxi) is the most commonly seen of the three species of boobies that occur in Galapagos. This species has beautiful and characteristic bright blue feet that are at the same time their trademark. The female is larger than the male and appears to have a larger dark pupil in the eye, contrasting with a yellow iris. This is due to a dark pigment around the pupil and not to any difference in size. Another way, a very easy one, to recognize the sex of a blue footed booby is by voice. Males whistle and females honk.
Courtship begins with a male advertising himself from a chosen site by “skypointing”. Once he has attracted a female, the two may parade to each other. Together they dance the “booby two-step”. If all goes well the dance peaks in mutual skypointing, face to face, and culminating in mating. They nest close to the shore on flat ground, with little or no vegetation. In large colonies there is almost continuous breeding and pairs may nest every seven to nine months. Clutch size is one to three, usually two but varies with locality. Eggs are laid five days apart and are incubated by both parents for 41 days. Chicks fledge 105 days later. When there is enough food in the ocean they may successfully rear all three chicks, but, in difficult times, they will raise only one. In today’s picture in the insert you can see clearly the way boobies incubate their eggs. These marine birds cover their eggs with their big webbed feet, which are irrigated with blood vessels. By either nestling down onto the eggs or raising the body so that cool air may circulate, boobies can maintain the temperature precisely around 39º C.
