Great Cormorant Identification

The size of the Great Cormorant is about 1m.

With a 1.5m wingspan.

The color of its plumage is mostly black with metallic sheens of blue, green, or bronze.

Its back is bronze-grey with dark edgings.

It has a white patch on the thigh during breeding season.

In breeding plumage, it has some longer white feathers on the head (especially in older individuals). These will fall off in summer.

Its silhouette is slender, with a long neck and tail.

It has an elongated, angular head.

Not to be confused with the European Shag which has a rounded forecrown with a small crest and a thinner beak.

Its eyes are green (ranging from emerald to turquoise).

Its beak is straight with a hooked tip and powerful.

A bare skin area near the lower mandible is yellow bordered by white extending to the cheeks and throat.

Its feet are black and webbed with four toes each.

Its non-breeding plumage is less shiny and less contrasting with duller cheeks.

The juvenile has a less distinct plumage with dark brown above and whitish below. Its beak is thinner.

One-year-old juveniles have whitish or mottled underparts with dark spots.

The plumage also varies depending on the subspecies. For example, North African subspecies have white chest and neck (in maroccanus or lucidus).

The Great Cormorant is noisy in colonies.

It produces guttural calls with sometimes different notes or rhythms (like trembling sounds).

It is often silent outside the colonies.

The Great Cormorant often stands with wings spread to dry its feathers and to impress predators.

The impermeability of its plumage is limited because it does not produce enough protective oil, hence the long drying sessions.

They gather on reefs and sandbanks, sometimes in very large numbers.

In winter, individuals gather in roosts in trees near rivers. They will return next winter, sometimes to the same tree.

The Great Cormorant swims with its body submerged, keeping its beak up.

Its flight resembles that of a goose: At a good height, the neck stretched forward, sometimes in formation. But it has a longer tail and a slightly hollowed neck.

It sometimes flies in chevrons (in V formation) to facilitate progression. The leader at the front, the others fly in its wake more easily. It will then be replaced to recover.

It flies with strong wingbeats and occasional glides.

Sometimes, it flies close to the water when the individual is isolated.

The Great Cormorant nests on the edge of cliffs, in trees near lakes or on the ground in reeds.

It nests in colonies from April to July.

Its nest is made of seaweed, reeds, wood, lined with finer materials.

Both parents build the nest. Reused each year, it can reach 1m in height and width.

During courtship, male and female raise their wings, revealing the white thigh patch, raise their tails, and point their necks and beaks skyward.

The chicks have a whitish down and a disproportionate neck.

Both parents take turns incubating so that each can feed.

The chicks are first fed with regurgitated liquid and then solid food taken from the parents' throats.

The Great Cormorant is piscivorous. It mainly eats fish and aquatic invertebrates.

It is a very good fisherman. Often solitary, it does not need much time to capture its prey.

Its characteristic dive is easily recognizable with a small leap forward.

A good swimmer, underwater sometimes for 1 min, it moves only using its webbed feet while keeping its wings close to its body.

It maintains good underwater vision with the nictitating membrane (a transparent third eyelid) that acts as diving goggles.

Back on the surface, it shakes its prey to stun it...

... and tosses it in the air to flip it and swallow it headfirst to prevent the fins from deploying.

Sometimes too greedy, trying to swallow prey too large for it, it dies of suffocation.

The Great Cormorant is an aquatic bird (often marine).

Cormorant comes from the Latin "Corvus marinus" meaning "sea raven", which reminds us of its habitat.

It lives on rocky, sandy coasts, near estuaries, lakes, and rivers.

It winters along the coasts.

Individuals are migratory in northern Europe.

In France, residents are found near the ocean coast and inland in the north of the country.