Gannets, Boobies

The Sulidae family, encompassing gannets and boobies, consists of medium-large coastal seabirds that dive from the air into the water to catch fish and other marine prey. These birds, which number 10 species, were traditionally grouped in the genus Sula but are currently divided into three genera: Sula (true boobies), Morus (gannets), and Papasula (the distinct Abbott's booby). Sulids have long and pointed wings, streamlined bodies for efficient diving, and colorful webbed feet used in mating displays. They also have a sharp beak with saw-like edges, forward-facing eyes for better vision, and a special gland for feather maintenance. Sulids are typically white with dark wingtips and tails, though some have darker upper parts and yellow-tinged heads like the gannets. These birds are found mainly in tropical and subtropical waters, sometimes venturing close to coasts or being swept away to distant lands. Sulids feed on mid-sized fish and marine invertebrates, often hunting in groups and occasionally following boats for easy meals. Their behavior includes using webbed feet and tightly sealed nostrils during dives. Sulids breed in colonies where males select and defend nesting sites, attracting females with specific displays and calls. They lay one to two eggs, which they incubate using heat from their webbed feet. Siblicide is common, with usually only one chick surviving to fledging, except in species like the Peruvian booby with larger clutches. The family is related to cormorants and darters and is considered the oldest lineage among them. Sulids appear to have diverged from their relatives over 50 million years ago, with fossils from as early as the Eocene era. The extant genera evolved around 23 million years ago. Various prehistoric genera of sulids are known only from fossils, with some still enigmatic. The taxonomy has undergone revisions with proposals to classify them under a new order, Phalacrocoraciformes or Suliformes, separate from the traditional Pelecaniformes.