Of the 36 Cormorant species worldwide, 6 reside in North America, most along the seacoast. The Double-crested Cormorant (Phalacrocorax auritus) is a goose-sized bird with a long neck and hooked bill. The adults are black and have a greenish sheen with bare orange skin on the face and throat. The crests for which these birds are named are so inconspicuous that they are generally not seen.
Double-crested Cormorants are most common and abundant along the Atlantic Coast. They often fly in V-shape formations like Canada geese but with their necks characteristically kinked in flight. Nesting colonies can be in trees near water, on cliff edges, or on the ground on islands. The birds rarely vocalize except in the nesting colony uttering guttural croaks and grunts.
Their plumage is not water repellant, so they often bask in the sun, holding their wings open to aid drying their feathers and regulate body temperature. Even so, only the outer feathers become heavy and soaked. An insulating layer beneath the external plumage protects them from chill when swimming underwater.
Cormorants swim low in the water and look very much like loons; cormorants, however, swim with their bills tipped up. This is an easy way to separate a cormorant from a loon. They are gregarious birds and hunt in small groups, flying low over the water searching for fish, their primary prey.
When they locate a school of fish, they land on the water and plunge headfirst below the water’s surface where they swim by using their wings and short, webbed feet. Cormorant’s eyes are both adapted to aerial and underwater vision. They have been known to dive 75 feet or more. Typically, they dive 5 or 25 feet deep, usually remaining submerged from 30 seconds to over a minute.