The double-crested cormorant, Nannopterum auritum, is a robust waterbird with a long neck and a stout, hooked bill. Its plumage is predominantly black, with some individuals displaying a greyish back and coverts. During the breeding season, adults develop distinctive nuptial crests above their eyes, which can be white, black, or a combination thereof. The species is named for these crests, and it also features a patch of orange-yellow facial skin. The double-crested cormorant measures 70–90 cm in length, with a wingspan of 114–123 cm, and weighs between 1.2 and 2.5 kg.
Adults in breeding plumage are mostly black with possible white crests and orange facial skin. Non-breeding adults lack the crests and have more yellowish facial skin. Juveniles are grey or brown with lighter underparts. The double-crested cormorant can be distinguished from the great cormorant by its more extensive yellow throat and bill, and from the neotropic cormorant by its range and size.
This species is found in a variety of aquatic environments, including rivers, lakes, and coastal areas. It is adaptable and can be seen perching with wings outstretched to dry its feathers after diving.
The double-crested cormorant is widely distributed across North America, from the Aleutian Islands in Alaska to Florida and Mexico. It is a migratory bird, with some populations moving southward in winter to ice-free coastal areas.
The double-crested cormorant is an adept swimmer and diver, using its feet for propulsion to catch prey. It is often observed standing with wings spread to dry its non-waterproof feathers. In flight, it has a characteristic posture with its bill tilted slightly upward.
