Double-crested Cormorant (Phalacrocorax auritus)
Field markings: 36 inches long, with a wingspan
of 52 inches. Dark colored with a long, slender orange bill and blue green eyes.
Feathers have a coppery iridescence when seen up close.
Habitat: Rocky coast, islands, bays, lakes, and rivers.
Seasonal appearance: All year with an increased wintering population.
Double-crested cormorants are long-necked black birds often seen sitting on piers and rocks in an upright position with wings open in a spread eagle posture. The yellow orange, unfeathered throat pouch of the double-crested cormorant distinguishes it from similar species. Adult birds in breeding plumage have a crest on either side of the head. Immature birds are dull brown to whitish on the chin, throat, and neck. In flight, the tail and head appear long, the neck crooked, and they often fly low near the water's surface. A traveling flock may form a line or wedge shape, but they fly silently, unlike noisy flocks of geese.
Life History and Behavior
Double-crested cormorants nest in colonies on islands in Narragansett Bay. Nests are built in live or dead trees, or on the ground, and are made of sticks, seaweed, and debris.
Double-crested cormorants feed on fish and aquatic invertebrates. They dive underwater and swim after fish using their strong paddle-like feet. The end of their bill is hooked to enable them to grasp onto fish. The outer layer of feathers on double-crested cormorants is not waterproof, and when wet it adds weight to the bird, making it easier to dive. The inner layer stays dry to provide insulation. After diving, double-crested cormorants stand on rocks or pilings and spread their wings out to dry the saturated flight feathers. Their eyes are adapted for both aerial and underwater vision. With a soft eye lens and strong eye muscles, they are able to change the shape of the lens to a more rounded shape to focus at shorter distances underwater.
Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.