Tuesday, November 12, 2013

Blue-footed Booby and Frigatebirds

Video: Blue-footed Booby and Magnificent Frigatebird, Galapagos (North Seymour)

The Blue-footed Booby (Sula nebouxii) is a marine bird in the family Sulidae, which includes ten species of long-winged seabirds. First studied extensively by Charles Darwin at the Galapagos. It belongs to the genus Sula, which comprises six species of 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 their feet up and down while strutting before the female. The female is slightly larger than the male and can measure up to 90 cm (36 in) long with a wingspan of up to 1.5 m (4.9 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. While it sometimes hunts alone, the Blue-footed Booby mainly hunts in groups.
The Blue-footed Booby usually lays one to three eggs at a time. The species practices asynchronous hatching, which means that eggs that are laid first are hatched before the consequent eggs, resulting in a growth inequality and size disparity between siblings. This results in facultative siblicide in times of food scarcity, making the Blue-footed Booby an effective model for studying parent-offspring conflict and sibling rivalry.

Magnificent Frigatebirds (Fregata magnificens) are a family, Fregatidae, of seabirds. There are five species in the single genus Fregata. They are also sometimes called Man of War birds or Pirate birds. Since they are related to the pelicans, the term "frigate pelican" is also a name applied to them. They have long wings, tails, and bills and the males have a red gular pouch that is inflated during the breeding season to attract a mate. Frigatebirds are pelagic piscivores that obtain most of their food on the wing. A small amount of their diet is obtained by robbing other seabirds, a behaviour that has given the family its name, and by snatching seabird chicks. Frigatebirds are seasonally monogamous, and nest colonially. A rough nest is constructed in low trees or on the ground on remote islands. A single egg is laid each breeding season. The duration of parental care in frigatebirds is the longest of any bird.