Great Cormorant

Informazioni

The Great Cormorant is a large, dark-plumaged aquatic bird found across a wide range of freshwater and coastal habitats. Renowned for its diving prowess, it feeds primarily on fish, which it pursues underwater. It is often seen perched with wings outstretched to dry its plumage, which is not fully waterproof.

Dimensioni e longevità

Lunghezza

80-100 cm

Apertura alare

130-160 cm

Peso

1.5-5.3 kg

Longevità

Up to 15-20 years in the wild

Dieta

Carnivore (piscivorous)

Caratteristiche fisiche

Piumaggio

Adults are predominantly glossy black with a metallic green sheen, especially on the back and wings. The throat and cheeks are white, bordered by a yellow gular patch. During breeding season, adults develop white patches on the flanks and fine white streaking on the head and neck.

Forma del becco

Long, slender, and hooked at the tip, dark grey to black. The upper mandible is slightly longer than the lower.

Colore degli occhi

Bright green, surrounded by a bare yellow patch of skin.

Colore delle zampe

Black, with fully webbed feet.

Caratteristiche distintive

Large size, dark plumage, prominent yellow gular patch, and the characteristic habit of perching with wings spread to dry. The hooked bill is also distinctive.

Aspetto giovanile

Juveniles are browner overall, with a paler, often whitish, belly and throat. The yellow gular patch is less developed, and they lack the white flank patches and head streaking of breeding adults. They gradually acquire adult plumage over 2-3 years.

Cambiamenti stagionali

During the breeding season, adults develop a prominent white patch on each flank (thigh patch) and fine white filoplumes on the head and neck. These features are lost outside the breeding season.

Dimorfismo sessuale

Males are generally slightly larger than females, but plumage is identical.

Come identificare

1. 1

   Size and Shape

   Look for a large, heavy-bodied waterbird with a long neck, stout body, and a long, hooked bill. Appears somewhat 'reptilian'.

2. 2

   Plumage (Adult)

   Glossy black plumage with a metallic sheen. Distinctive white throat and cheek patch, bordered by a yellow-orange gular skin. Breeding adults show white flank patches and fine white head streaking.

3. 3

   Plumage (Juvenile)

   Browner overall with a paler, often whitish, belly and throat. Lacks the strong yellow gular patch and breeding adornments of adults.

4. 4

   Behavior

   Often seen diving for fish, then perching with wings outstretched to dry. Flies with strong, direct wingbeats, often in V-formation.

5. 5

   Habitat

   Found in both freshwater (large lakes, rivers) and coastal marine environments.

Habitat e areale

Biomi

Coastal marine environments, large freshwater lakes, rivers, estuaries, and reservoirs.

Areale geografico

Widespread across Europe, Asia, Africa, Australasia, and parts of North America (Greenland and eastern Canada).

Fascia altitudinale

Typically found from sea level up to a few hundred meters, primarily associated with water bodies.

Ambienti preferiti

Prefers shallow, productive waters for foraging, with nearby undisturbed areas for roosting and nesting, such as cliffs, islands, or tall trees.

Comportamento

Periodo di attività

Diurnal, actively foraging during daylight hours.

Abitudini alimentari

Primarily piscivorous, diving from the surface to pursue fish underwater. They use their powerful webbed feet for propulsion and their hooked bill to grasp prey. They can dive to considerable depths and remain submerged for up to a minute. They often hunt cooperatively in groups.

Comportamento sociale

Highly social, especially outside the breeding season, forming large roosting and feeding flocks. Breeds colonially, often in mixed-species colonies with other waterbirds.

Tipo di volo

Strong, direct flight with powerful, steady wing beats. Often flies in V-formations or in long lines when moving between feeding and roosting sites. Appears heavy in flight, with the neck extended.

Migrazione

Northern populations are migratory, moving south for the winter. Southern populations are largely resident or undertake short-distance dispersal. Migration occurs in broad fronts, often along coastlines or major river systems.

Territorialità

Territorial around the nest site during the breeding season, but generally tolerant of other cormorants outside this period.

Riproduzione

Stagione riproduttiva

Varies geographically, typically from February to July in temperate regions, year-round in tropical areas.

Abitudini di nidificazione

Nests colonially on cliffs, rocky islets, in trees, or on artificial structures like derelict buildings or platforms. Nests are bulky structures made of sticks, seaweed, and other vegetation, cemented with guano.

Dimensione della covata

3-4 eggs

Descrizione dell'uovo

Typically 3-4 eggs (range 1-6), pale blue or greenish-blue, covered with a chalky white layer that often gets stained.

Periodo di incubazione

28-31 days

Periodo di involo

50-60 days, but young may leave the nest earlier and remain in the vicinity, being fed by parents.

Cure parentali

Both parents share incubation duties and care for the young. Chicks are altricial, born naked and helpless, and require extensive parental feeding.

Dove trovarlo

Consigli sul campo

1. Look for drying behavior. Cormorants frequently perch with their wings spread wide to dry their feathers after diving. This is a very characteristic posture and makes them easy to spot.
2. Observe diving patterns. Watch for birds that dive smoothly from the surface, often disappearing for 30-60 seconds before resurfacing, usually with a fish.
3. Check roosting sites. At dawn and dusk, observe large groups flying to and from communal roosts, which can be on isolated trees, cliffs, or artificial structures.
4. Listen at colonies. During the breeding season, their guttural calls can help locate active nesting colonies.

Specie simili

Fatti rapidi

Diet:

Fish

Habitat:

Freshwater and coastal marine

Sociality:

Colonial

Distinguishing Feature:

Yellow gular patch, white throat, drying wings

Conservation Status:

Least Concern

Curiosità

• Cormorants have less preen oil than most other waterbirds, which allows their feathers to become waterlogged. This reduces buoyancy, making it easier for them to dive and pursue fish underwater. They then need to dry their wings after fishing.
• In some parts of Asia, particularly China and Japan, cormorants have historically been trained by fishermen to catch fish. A ring is placed around the bird's neck to prevent it from swallowing larger fish, which are then retrieved by the fisherman.
• The Great Cormorant is one of the most widespread cormorant species globally, with a distribution spanning multiple continents.
• Despite their large size, cormorants are agile underwater predators, capable of rapid acceleration and maneuvering to catch fast-moving fish.

Classificazione scientifica

Regno

Animalia

Phylum

Chordata

Classe

Aves

Ordine

Suliformes

Famiglia

Phalacrocoracidae

Genere

Phalacrocorax

Specie

Phalacrocorax carbo

Esplora Great Cormorant