It is endemic to the Cape Verde Islands and has an all dark, slim bill, and darker head and upperparts than Cory's.

Based on the lack of hybridization and differences in mitochondrial DNA, morphology and vocalization, the complex was split into two separate species.

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.

In late summer and autumn, most birds migrate into the Atlantic as far north as the south-western coasts of Great Britain and Ireland.

Cory's shearwater feeds on fish, molluscs and offal, and can dive deep (15 m (49 ft) or more) in search of prey.