The Manx Shearwater (Puffinus puffinus) is a medium-sized shearwater.
The prefix Manx, meaning from the Isle of Man, originated owing to the once large colony of Manx Shearwaters found on the Calf of Man (a small island just south of the Isle of Man). The species had declined there owing to the accidental introduction of rats from a shipwreck in the late eighteenth century; the rats have, however, recently been removed from the Calf of Man allowing Shearwater numbers to increase.
This species breeds in the North Atlantic, with major colonies on islands and coastal cliffs around Great Britain and Ireland. These birds have been nesting along the Atlantic coast of northeastern North America since about 1970. They nest in burrows, laying one white egg which is only visited at night to avoid predation by large gulls. The islands are usually free of mammalian predators. They form life-long monogamous pair-bonds.
This bird is 30-38 cm long, with a 76-89 cm wingspan. It has the typically "shearing" flight, dipping from side to side on stiff wings with few wingbeats, the wingtips almost touching the water. This bird looks like a flying cross, with its wing held at right angles to the body, and it changes from black to white as the black upperparts and white undersides are alternately exposed as it travels low over the sea.
This is a gregarious species, which can been seen in large numbers from boats or headlands, especially on passage in autumn. It is silent at sea, but at night the breeding colonies are alive with raucous cackling calls. The Manx Shearwater feeds on small fish (particularly herring, sprat and sardines), crustaceans, cephalopods and surface offal. The bird forages individually or in small flocks, and it makes use of feeding marine mammals and schools of predatory fish, which push prey species up to the surface. It does not follow boats.
They are extraordinarily long-lived. A Manx Shearwater breeding on Copeland Island, Northern Ireland, was as of 2003/2004 the oldest known living wild bird in the world: ringed as an adult (at least 5 years old) in July 1953, it was retrapped in July 2003, at least 55 years old.