Sooty Tern

The sooty tern is a seabird of the tropical oceans that can fly for years at a time, skimming the sea surface for food and returning to land only to breed on islands throughout the equatorial zone. It is a medium-large tern, similar in size to the Sandwich tern at 36–45 cm long. Six subspecies are currently accepted; the form nubilosus breeds across the Indian Ocean from the Red Sea to Indonesia and in the Philippines (Wikipedia, general species account).