What used to be called Cory’s Shearwater has now been split into two species. Cory’s Shearwater (Calonectris borealis) and Scopoli’s Shearwater (Calonectris diomedea) Both species can be found off the Eastern coast of the U.S. usually far offshore. Cory’s Shearwater breeds in the Atlantic and Scopoli’s Shearwater breeds in the Mediterranean. Scopoli’s Shearwater is less common than Cory’s Shearwater off of the Eastern U.S. coast.
The name Scopoli’s comes from the Italian naturalist Giovanni Antonio Scopoli. When Cory’s Shearwaters are present off the South Florida Coast, we often see Scopoli’s Shearwaters mixed in with them. These two species can be challenging to I.D. in the field since most sightings will be from a rocking boat. The Scopoli’s Shearwater is slightly smaller with a slightly darker head. The primary feathers are lighter than the darker primary feathers of Cory’s Shearwater.
I took two different photos, one of a Scopoli’s Shearwater and one of a Cory’s Shearwater. I photoshopped the photos together so that the differences between these two species can be seen. The Scopoli’s Shearwater is on the left and the Cory’s Shearwater is on the right.
