Cory's Shearwater

Overview

Cory's Shearwater is one of the larger shearwaters found in the Atlantic, notable for a relatively uniform brownish-gray head and upperparts without the strong cap-and-collar contrast seen in some relatives, along with a distinctly yellowish bill. Its flight is often described as slower and more languid than other large shearwaters.

It breeds on islands across the eastern Atlantic and disperses widely across the ocean outside the breeding season, sometimes reaching well offshore of North America.

Cory's Shearwater feathers reflect the bird's overall paler, less contrasty plumage compared to some relatives.

• Head and neck: Fairly uniform grayish-brown without a sharply defined dark cap or pale collar, unlike the Great Shearwater.
• Upperparts: Brownish-gray, generally smoother in tone than the scaly-patterned back of the Great Shearwater.
• Underparts: Clean white, without the dark belly patch seen in Great Shearwater.
• Flight feathers: Long and broad, consistent with the bird's larger size and slower flight style.
• Compared to Great Shearwater: Cory's lacks strong head contrast and a dark belly patch, appearing overall softer and less patterned.

Adults show a fairly uniform brownish-gray head, neck, and upperparts, with clean white underparts and underwings. Sexes look alike. Juveniles resemble adults closely, with subtle differences in feather freshness. Molt occurs largely outside the breeding season as the bird ranges across the open Atlantic.

Cory's Shearwaters breed on islands across the eastern Atlantic and Mediterranean, nesting in burrows and rock crevices, then disperse widely across the Atlantic Ocean outside the breeding season, including waters off the eastern coast of North America. They are strongly pelagic, favoring warm and temperate offshore waters.

This shearwater feeds on small fish and squid, often by surface-seizing and shallow pursuit-diving, and readily follows fishing vessels to feed on discarded catch. Its flight is comparatively slow and languid, with long glides on bowed wings rather than the quicker, more energetic style of some smaller shearwaters. Nesting occurs in burrows and crevices on remote islands, with a single egg laid per season and visits to the colony concentrated at night. Calls are loud, wailing or braying notes given at breeding colonies after dark.