Blue-footed booby

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 is a sexually selected trait. Males display their feet in an elaborate mating ritual by lifting them up and down while strutting before the female. The female is slightly larger than the male and can measure up to 90 cm (35 in) long with a wingspan of up to 1.5 m (5 ft). The natural breeding habitats of the blue-footed booby are the tropical and subtropical islands of the Pacific Ocean. It can be found from the Gulf of California down along the western coasts of Central and South America down to Peru. Approximately one half of all breeding pairs nest on the Galápagos Islands. Its diet mainly consists of fish, which it obtains by diving and sometimes swimming underwater in search of its prey. It sometimes hunts alone, but usually hunts in groups. The blue-footed booby usually lays one to three eggs at a time. The species practices asynchronous hatching, in contrast to many other species whereby incubation begins when the last egg is laid and all chicks hatch together. This results in a growth inequality and size disparity between siblings, leading to facultative siblicide in times of food scarcity. This makes the blue-footed booby an important model for studying parent–offspring conflict and sibling rivalry. The blue-footed booby was described by the French naturalist Alphonse Milne-Edwards in 1882 under the current binomial name Sula nebouxii. The specific epithet was chosen to honor the surgeon, naturalist, and explorer Adolphe-Simon Neboux (1806-1844). There are two recognized subspecies: Its closest relative is the Peruvian booby. It is likely that the two species split from each other recently due to their shared ecological and biological characteristics. A 2011 study of multiple genes calculated the two species diverged between 1.1 and 0.8 million years ago. The name booby comes from the Spanish word bobo ('stupid', 'foolish', or 'clown') because the blue-footed booby is, like other seabirds, clumsy on land. They are also regarded as foolish for their apparent fearlessness of humans. The blue-footed booby is on average 81 cm (32 in) long and weighs 1.5 kg (3.3 lb), with the female being slightly larger than the male. Its wings are long and pointed and brown in color. The neck and head of the blue-footed booby 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 S. n. excisa that breeds on the Galápagos Islands is larger than the nominate subspecies and has lighter plumage especially around the neck and head. The Peruvian booby is similar in appearance but has grey feet, whiter head and neck, and white spots on its wing coverts. The ranges of the two species overlap in the waters of northern Peru and southern Ecuador.