Great Cormorant (Phalacrocorax carbo) — identification, habitat & look-alikes

Along rocky shores of the northeastern United States, Great Cormorants stand out as large, heavy cormorants with white throats and massive bills. They dive for fish, then perch with their wings spread to dry.

Appearance

Appearance: This heavyset bird is 33–35 in (84–90 cm) long with a thick neck, blocky head, and heavy hooked bill. Adults have a white throat patch; breeding adults also show a white patch on each thigh.

Look-alikes

Double-crested CormorantNannopterum auritum

Double-crested Cormorants are smaller and slimmer, with more orange-yellow bare skin around the bill. Great Cormorants have a broad white throat patch, and breeding adults show square white thigh patches.

Why they get mixed upThe more common Double-crested Cormorant often shares the same shores and perches.

Where it lives

Typical habitats: rocky Atlantic coasts
islands and sea cliffs
jetties and breakwaters
Range: In North America it is concentrated along Atlantic Canada and the northeastern U.S. coast, with smaller numbers wintering southward and on a few large rivers. Inland records are unusual.
Seasonal presence: It is mainly coastal and is much less widespread in the United States than the Double-crested Cormorant (Nannopterum auritum).
Preferred conditions: It favors shallow coastal water near rocky resting and nesting sites, though wintering birds sometimes use major rivers.
When it’s recorded: Recorded Sep–May most years
327 observations in the US · 10 years · for reference

Behavior

Diet: It dives from the surface for bottom-dwelling fish, including fish that shelter among submerged rocks.
Activity: After diving, it often perches on rocks, pilings, or jetties and holds its wings open to dry.
Social life: It forms flocks year-round and nests in , but North American flocks are often smaller than those of Double-crested Cormorants.

Life cycle

Nest: Pairs usually nest on flat ground or ledges on rocky islands and cliffs. The nest is a mound of sticks, seaweed, and other debris.
Clutch size: 1–7 eggs

Name and classification

About the name: North American birds belong to the North Atlantic Phalacrocorax carbo carbo; birds in other parts of the world belong to other subspecies.

Conservation

IUCN Red List: LCLeast ConcernLow risk of extinction
Status: Populations in northeastern North America appear generally stable, although a 2016 account noted a steep decline in Maine.

12 sources