Cory's Shearwater vs Great Shearwater

In short

Cory's Shearwater and Great Shearwater can be distinguished by their head markings and underwing patterns. Cory's Shearwater has a more uniform head and cleaner underwing, while Great Shearwater features a distinctive dark cap and a brown belly patch.

Identification tips

• Look for the dark cap and brown belly patch on Great Shearwater.
• Check the underwing pattern: Cory's has cleaner white underwings, while Great has brown markings.
• Consider the geographic location and season: Great Shearwater migrates north in the non-breeding season, while Cory's Shearwater is more stationary in the North Atlantic.

Size

Both species are similar in size, but Cory's Shearwater is slightly larger and bulkier.

Plumage

Cory's Shearwater has a more uniform grayish-brown head and cleaner white underwings. In contrast, Great Shearwater has a dark cap, a brown belly patch, and underwings with variable brown markings.

Behaviour

Both species exhibit similar flight patterns typical of shearwaters, with long glides and few wingbeats.

Habitat

Both species are pelagic and often found far from land, but Great Shearwater breeds in the South Atlantic and migrates north, while Cory's Shearwater is more associated with the Mediterranean and North Atlantic.

Voice

Vocalizations are not a reliable field mark for distinguishing these species at sea.