This shearwater is identifiable by its size, at 45?56 cm (18?22 in) in length and with a 112?126 cm (44?50 in) wingspan. It has brownish-grey upperparts, white underparts and a yellowish bill. It lacks the brown belly patch, dark shoulder markings and black cap of the great shearwater. 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 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.


Habitat and Distribution

This species breeds on Madeira, the Azores and the Berlengas Archipelago in Portugal and the Canary Islands in Spain. 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. The biggest colony is located in Savage Islands, Madeira.


Feeding

Cory's shearwater feeds on fish, molluscs and offal, and can dive deep (50 ft (15 m) or more) in search of prey. It readily follows fishing boats, where it indulges in noisy squabbles.


Breeding

They nest on open ground or among rocks or less often in a burrow where one white egg is laid. The burrow is visited at night to minimise predation from large gulls.


Calls and Songs

It is silent at sea, but at night the breeding colonies are alive with raucous cackling calls.