Cory's
Shearwater is a large Shearwater species of the Atlantic. They breed
in the Mediterranean and on islands in the eastern Pacific, but wander
widely after the breeding season. In North America, they are most
often seen off the East Coast in summer or early fall. It is thought
that most birds seen off North America are likely juveniles or non-breeding
adults. They tend to prefer areas with relatively warmer waters, and
thus in North American waters, are often seen in and around the Gulf Stream.
Habitat: Nests on islands with suitable nesting
habitat, either islands with soil suitable for digging burrows, or rocky
islands with crevices for nesting. Outside of the breeding season,
they disperse widely in the Atlantic, usually over warmer water areas or
areas with upwelling currents.
Diet: Feeds mostly on fish, squid, and small
crustaceans.
Behavior: Forages by flying above the water's
surface, and plunge diving from near the water's surface. They will
also swim on the water's surface and grab items with their bill. They
will also follow fishing boats for discarded scraps.
Nesting: Colonial breeder. Nests are usually
burrows in the ground, but they will also sometimes use crevices in rocky
areas, or nest on the ground in thickly vegetated areas. The nest
itself is a basic pile of shells, pebbles, and other debris. The female lays
a single egg, and both parents help to incubate it. Upon hatching,
both parents help to feed and raise the nestling.
Song: Usually silent
Migration: Cory's Shearwaters breed in the
Mediterranean, as well as islands in the eastern Atlantic. In North
America, most birds are immatures and non-breeding birds, and are seen in
the summer months through early fall.
Similar Species:
Most likely to be confused with Great
Shearwater in range. The two species are similar in size, with
light coloring below and dark coloring above, but Cory's Shearwaters have a
much "cleaner" look on the underwing, with white and a dark border.
Cory's Shearwaters also have a thick yellow bill, vs. the thin black bill of
a Great Shearwater.
Conservation Status: Populations of Cory's
Shearwater may be decreasing, but they still are found over a wide range and
have strong populations overall.
The IUCN lists the
Cory's Shearwater as a species of "Least Concern".