Sooty Tern

The sooty tern is a medium-large tern, 36–45cm long with a wingspan of 82–94cm, similar in size to a Sandwich tern. It is black to blackish-brown above and white below, with a white forehead, long wings, a moderately forked black tail edged white, and black legs and bill. It is darker-backed than the smaller bridled tern, with a broader white forehead and no pale neck collar. Juveniles are grey-black above and below with pale fringes that give a scaly look. Its call is a loud, piercing wide-a-wake (Wikipedia, general species account).

It is a bird of the tropical oceans that can stay at sea for years at a time. Its plumage lacks waterproofing oil, so it cannot rest on the water and spends that whole time on the wing, skimming fish from the surface, often in large flocks. It comes to land only to breed, in colonies on rocky or coral islands, laying a single egg in a scrape or hole (Wikipedia, general species account).