The Great Cormorant (Phalacrocorax carbo): The Expert Diver of Our Waters

A Great Cormorant perched on a post, spreading its wings to dry in the sun. — The Great Cormorant, an iconic silhouette on coasts and waterways, drying its less-waterproof plumage.

An Unmistakable Silhouette

The Great Cormorant (Phalacrocorax carbo) is one of those unforgettable birds that leaves a lasting impression once you spot it – standing tall and proud with its striking dark silhouette. You might have seen one resting on a dock post or a rocky ledge, wings spread wide as if it's putting on a show.

Here’s the intriguing part: it’s actually drying its feathers! Unlike other seabirds that boast super waterproof feathers, the cormorant’s plumage gets soaked – and that’s by design. This smart adaptation allows it to glide through the water like a torpedo, diving deeper than birds like the Brown Pelican could ever imagine to catch fish.

Our Ornithologist's Tip

By the Les-Oiseaux.com team, published on September 6, 2025

My advice: To observe the Great Cormorant, favor large freshwater bodies (lakes, wide rivers) or coastal areas (estuaries, bays, cliffs). You will often see it fishing by diving, or perched on rocks, buoys, or dead trees, with its wings wide open to dry its plumage after a fishing session. This is an iconic posture! It is generally not very shy and quite easy to approach discreetly.

Identification: Black Cormorant, White, or Juvenile?

One of the main questions when identifying a cormorant is its plumage color. Is it black, white, or black and white? The answer depends on its age and the season.

The Adult: The "Black Cormorant"

Outside the breeding season, the adult is an almost entirely black cormorant, with metallic green and blue sheens. This appearance gives it the name "black cormorant". Its powerful bill is hooked at the tip. There is no visible difference between the male and female.

The Breeding Plumage: The Appearance of White

During the breeding season (from winter to spring), the adult dons a spectacular breeding plumage. A distinctive white patch appears on each flank, and its head and neck become covered with fine white feathers, giving it a grizzled look. This is the black and white cormorant often seen early in the year.

The Juvenile: The "White-Bellied Cormorant"

The juvenile Great Cormorant looks very different from the adult. Its plumage is much duller, dark brown on the back and wings, while its belly, breast, and the front of its neck are whitish. This young bird is often mistakenly called a "white cormorant" or "white-bellied cormorant". It will take several years for the juvenile to acquire its full dark adult plumage.

A juvenile cormorant, recognizable by its white belly and breast contrasting with its brown back. — The juvenile cormorant's plumage, with its white belly, is often a source of confusion.

Scientific Dimensions and Records (Great Cormorant)

Characteristic	Male	Female	Record / Average
Length	80 – 100 cm	80 – 100 cm	80 – 100 cm (adults)
Weight	2.7 – 3.7 kg	1.8 – 3 kg	1.8 – 3.7 kg (adults)
Wingspan	130 – 160 cm	130 – 160 cm	130 – 160 cm (adults)
Diet	Piscivorous	Piscivorous	Fish (primarily), aquatic invertebrates, amphibians, mollusks
Life Expectancy	15 – 20 years	15 – 20 years	Up to 23 years (in the wild)

These figures confirm that the Great Cormorant is a large aquatic bird, recognizable by its dark plumage and characteristic silhouette, an exceptional diver and fisher.

Calls and Vocalizations: Guttural Cries Mainly in Colonies

The Great Cormorant is generally a discreet and not very vocal bird outside the breeding season. It is rarely heard when fishing or resting alone. It is primarily within its nesting colonies, often noisy and odorous, that the Great Cormorant becomes more expressive.

Its vocalizations are then a variety of guttural, deep, and hoarse sounds, which can include croaks, grunts, and a kind of "squawks." These calls are used for various social interactions within the colony, such as courtship displays, territorial disputes around the nest, or communication between parents and young.

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Habitat and Distribution

Originally a coastal bird, the Great Cormorant has experienced a remarkable inland expansion. It is found along all maritime coasts, but also on major rivers (Loire, Seine, Rhine...), lakes, ponds, and reservoirs. It settles wherever the fish supply is sufficient. Its presence is particularly noticeable in winter, when northern populations come to reinforce local numbers.

Distribution Map

Diet: A Master Fisher

The Great Cormorant is a formidably efficient piscivorous predator. It fishes by diving underwater, propelling itself with its large webbed feet. It can remain submerged for over a minute and reach depths of several meters to pursue and capture medium-sized fish. After fishing, it swallows its prey headfirst before returning to a perch to digest and dry its wings.

Nesting & Reproduction

Cormorants nest in colonies, called "cormorantries," often located on coastal cliffs, in trees near water, or on rocky islets. The nest is a large structure made of branches and seaweed, consolidated with droppings. The female lays 3 to 4 chalky, bluish-white eggs. Both parents take turns incubating and feeding the altricial chicks, which are entirely dependent on them.

Conservation Status

Once threatened, the Great Cormorant has benefited from protection measures that have allowed its populations to recover spectacularly in Europe and North America. It is now listed as "Least Concern" (LC) by the IUCN. However, this success has led to conflicts with professional and recreational fishers who accuse it of taking significant quantities of fish from rivers and fish farms.

Frequently Asked Questions (FAQ)

Why do Great Cormorants spread their wings?

Unlike many aquatic birds whose feathers are very waterproof, those of the Great Cormorant absorb water to facilitate diving. After fishing, it spreads its wings in a characteristic "V" shape to dry them in the wind and sun. This posture allows it to regain its lightness for flight and to retain body heat once dry.

What does the Great Cormorant primarily eat?

The diet of the Great Cormorant is almost exclusively piscivorous. It feeds on a wide variety of medium-sized fish, which it catches by diving and pursuing them underwater. It may occasionally consume eels, amphibians, or large aquatic invertebrates, but fish constitute the major part of its diet.

Is the Great Cormorant a migratory bird?

Yes, many populations of Great Cormorants are migratory. Birds nesting in the northernmost regions of its range (Scandinavia, Russia, Canada) move south to winter in areas where waters do not freeze. Southern populations or those in temperate regions are often sedentary or migrate only short distances.

Where does the Great Cormorant build its nest?

The Great Cormorant nests in colonies, often mixed with other species of aquatic birds. It builds its nest primarily in trees (sometimes in large numbers, which can damage vegetation), on rocky cliffs along the coasts, or sometimes directly on the ground on isolated islands or in the reeds of large wetlands.