Cory's Shearwater

Cory's Shearwater, Calonectris diomedea, is a large shearwater in the seabird family Procellariidae.

This species breeds on islands and cliffs in the Mediterranean, with the odd outpost on the Atlantic coast of Iberia. The nest is in a burrow or among rocks, and is visited at night to minimise predation from large gulls. In late summer and autumn, most birds migrate into the Atlantic as far north as the south-western coasts of Great Britain and Ireland. They return to the Mediterranean in February.

This bird flies with long glides, and always with wings bowed and angled slightly back, unlike the stiff, straight winged flight of the similarly-sized Great Shearwater.

This shearwater is identifiable by its size, brownish grey upperparts, white underparts and yellowish bill. It lacks the brown belly patch, dark shoulder markings and black cap of Great Shearwater.

Cory's Shearwater feeds on fish, molluscs and offal. It readily follows fishing boats, where it indulges in noisy squabbles. This is a gregarious species, which can be seen in large numbers from ships or appropriate headlands. The Bay of Biscay ferries are particularly good for this species. It is silent at sea, but at night the breeding colonies are alive with raucous cackling calls.

This bird was named after the American ornithologist Charles Barney Cory.