The Blue-footed booby (Sula nebouxii) is a marine bird native to subtropical and tropical regions of the eastern Pacific Ocean. It is one of six species of the genus Sula - known as boobies. It is easily recognizable by its distinctive bright blue feet which play a key role in courtship rituals with the male visually displaying his feet to attract mates during the breeding season.
The wings of the Blue-footed booby are long, pointed, and brown in color. The neck and head are light brown with white streaks, while the belly and underside exhibit pure white plumage. Its eyes are placed on either side of its bill and oriented towards the front, enabling excellent binocular vision. Its eyes are a distinctive yellow, with the male having more yellow in its irises than the female. Blue-footed booby chicks have black beaks and feet and are clad in a layer of soft white down. The subspecies that breeds on the Galápagos Islands is larger than the nominate subspecies and has lighter plumage, especially around the neck and head. Since the Blue-footed booby preys on fish by diving headlong into the water, its nostrils are permanently closed, and it has to breathe through the corners of its mouth. Its most notable characteristic is its blue-colored feet, which can range in color from pale turquoise to deep aquamarine. Males and younger birds have lighter feet than females.
Blue-footed boobies occur among the continental coasts of the eastern Pacific Ocean from California to the Galápagos Islands south into Peru. They spend most of the time in the inshore waters and only come out on land to nest, which they do along the rocky coasts with little vegetation.
Blue-footed boobies are active during the day and outside of the breeding season spend all their time in the water. They hunt by diving into the ocean after prey, sometimes from a great height, and can also swim underwater in pursuit of their prey. They can hunt singly, in pairs, or in larger flocks. Boobies travel in parties of about 12 to areas of water with large schools of small fish. When the lead bird sees a fish shoal in the water, it signals to the rest of the group, and they all dive in unison, pointing their bodies down like arrows. Prey is usually eaten while the birds are still under the water. Individuals prefer to eat on their own instead of with their hunting group, usually in the early morning or late afternoon. Males and females fish differently, which may contribute to why blue-foots, unlike other boobies, raise more than one young. The male is smaller and has a proportionally larger tail, which enables the male to fish in shallow areas and deep waters. The female is larger and can carry more food. Blue-footed boobies communicate with the help of raucous or polysyllabic grunts or shouts and thin whistling noises. The males may throw up their heads and whistle at a passing, flying female. Their ritual displays are also a form of communication.
Blue-footed boobies have a carnivorous (piscivorous) diet. They are specialized fish eaters, feeding on small schooling fish such as sardines, anchovies, mackerel, and flying fish. They will also take squid and offal.
Blue-footed boobies are monogamous and form pairs. They are opportunistic breeders and have a very interesting courtship ritual which includes the male flaunting his blue feet and dancing to impress the female. The male begins by showing his feet, strutting in front of the female. Then, he presents nest materials and finishes the mating ritual with a final display of his feet. The dance also includes "sky-pointing", which involves the male pointing his head and bill up to the sky while keeping the wings and tail raised. Blue-footed boobies nest in colonies. Each pair may use and defend two or three nesting sites, which consist of bare black lava in small divots in the ground until they develop a preference for one a few weeks before the eggs are laid. The female lays 2 or 3 eggs and both parents take turns incubating the eggs, while the non-sitting bird keeps watching. The incubation period is 41-45 days and usually, only 1 or 2 chicks are hatched. The male provides food for the young in the first part of their lives because of his specialized diving. The female takes over when the demand is higher. Chicks feed off the regurgitated fish in the adult's mouth. If the parent does not have enough food for all of the chicks, it will only feed the biggest chick, ensuring that at least one will survive. Young females usually start breeding when they are 1 to 6 years old, while males attain reproductive maturity when they are 2 to 6 years old.
Blue-footed boobies are not considered endangered at present, however, climate change and shortage of food may cause declines in their population in the future.
According to the Avian Conservation and Ecology resource, the total population size of the Blue-footed booby is 6,423 individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
