Great Cormorant

Overview

The Great Cormorant is one of the largest and most widespread cormorants, found across much of Europe, Asia, Africa, and Australia. Its plumage is glossy blackish with a bronze-green sheen, set off by a patch of white throat feathers and a bordering yellow gular skin patch.

During the breeding season, adults develop a striking white patch of feathers on each flank, a feature not present outside the breeding period, making feather appearance somewhat season-dependent for this species.

Great Cormorant feathers are glossy blackish with additional white markings during the breeding season.

• Body feathers: Glossy black with a bronze-green iridescent sheen in good light, larger and heavier than those of the Double-crested Cormorant given the bird's greater size.
• Throat feathers: A patch of white feathering on the chin/throat, bordered by yellow bare skin.
• Flank feathers (breeding): A conspicuous white patch appears on each flank during the breeding season, absent the rest of the year.
• Compared to Double-crested Cormorant: Great Cormorant is larger overall with a white throat patch and breeding flank patch, both lacking in Double-crested Cormorant.

Adults are glossy black with a bronze-green sheen, a white throat patch bordered by yellow facial skin, and a temporary white flank patch that develops during the breeding season and is lost afterward. Sexes look alike. Juveniles are browner overall with a paler, whitish belly, gradually acquiring the glossier adult black plumage with maturity. Molt occurs annually, with the breeding-season white flank patch feathers molted out again after the nesting period.

Great Cormorants occupy a very wide range across Europe, Asia, Africa, and Australia, using coastal waters, estuaries, lakes, and rivers. Some populations are resident year-round while northern populations migrate south for the winter, and the species shows considerable ecological flexibility between marine and freshwater habitats.

This cormorant feeds by diving from the surface and swimming underwater in pursuit of fish, often foraging in loose groups and perching afterward with wings spread to dry, similar to other cormorants. Nesting occurs colonially in trees, on cliffs, or on the ground depending on the region, with a clutch of several eggs. Calls are low guttural croaks and grunts given mainly at breeding colonies.