Great Cormorant

Phalacrocorax carbo

Order: Suliformes / Family: Phalacrocoracidae

Wikimedia Commons

black large waterbird coastal wetland migratory common widespread colonial

About the Great Cormorant

The Great Cormorant, Phalacrocorax carbo, is a large, robust waterbird noted for its adaptability and broad geographic distribution. This species inhabits a wide range of aquatic environments, from coastal seas to inland freshwater lakes and rivers across Europe, Asia, Africa, and North America. Its ecological role is significant, as it acts as a top predator in many of these ecosystems, controlling fish populations and thus maintaining ecological balance. During breeding seasons, Great Cormorants form large colonies, favoring isolated islands and coastal cliffs, though they can also be found in trees near water bodies. In winter, they gather in sizable flocks, showcasing their highly social nature. The bird's ability to thrive in both saltwater and freshwater habitats speaks to its remarkable adaptability. In Europe, the Great Cormorant is a common sight along the Atlantic coastlines and inland waterways. In Asia, it ranges extensively from the temperate zones to the subtropics, demonstrating a wide tolerance for various climatic conditions. In Africa, it is found along major rivers and lakes, while in North America, its presence is more localized, seen primarily along the northeastern seaboard. The Great Cormorant's significance extends beyond its ecological role; it has cultural implications as well. In some Asian cultures, trained cormorants have been used in traditional fishing practices for centuries. Their ability to dive and catch fish with precision has long fascinated humans, adding an element of intrigue to their presence. Overall, the Great Cormorant is a testament to avian adaptability and ecological significance, thriving across continents and contributing to the biodiversity of the regions it inhabits.

The Great Cormorant belongs to the family Phalacrocoracidae, within the order Suliformes. These birds typically live average lifespan is 10-15 years, with a maximum recorded of over 20 years..

How to Identify a Great Cormorant

Adults possess glossy black plumage, but during the breeding season, they develop distinct white patches on their thighs and face. Their eyes are an iridescent green, providing a striking contrast to their dark feathers. The hooked bill is long and yellow at its base, ideal for catching slippery prey. Juveniles differ slightly, displaying a mottled brown color with paler underparts, gradually darkening as they mature. Males are generally larger than females but share similar plumage. When observing in the field, one might confuse the Great Cormorant with the Double-crested Cormorant. However, the Great Cormorant is larger and lacks the prominent crests of its counterpart. In flight, it presents a distinctive silhouette with its long neck outstretched and wings held flat, beating steadily. When perched, it often adopts a classic cormorant pose, wings spread wide to dry after diving.

Having trouble telling birds apart? Upload a photo to our bird identification tool for an instant species match.

Great Cormorant Habitat and Range

Preferred Habitat

Great Cormorants occupy a range of habitats, predominantly aquatic environments. They are found in coastal regions, including rocky shores and estuaries, as well as inland bodies of water like lakes, rivers, and wetlands. In Europe, they are commonly seen in large river systems and are particularly abundant in the Baltic and North Seas. Their habitat choice is influenced by the availability of fish, their primary food source. During the breeding season, they favor secluded spots such as islands or tall trees near water, offering protection from predators. These birds are adaptable to urban environments, where they can be seen in city harbors and lakes, often causing conflicts due to their foraging habits.

Geographic Range

The Great Cormorant has an extensive range across multiple continents. It breeds throughout much of Europe, from Scandinavia down to the Mediterranean. In Asia, its range stretches from the Middle East to the coasts of China and Japan. African populations are found mainly along the Nile and in sub-Saharan regions. In North America, they are primarily located along the northeastern coast but have been expanding westward. During winter, northern populations migrate southward to escape harsh conditions, traveling along established migration corridors to reach warmer areas. High-density populations can be observed along the coasts of the British Isles and the Dutch Wadden Sea, where they take advantage of abundant fish stocks.

Want to know which birds visit your area? Browse our backyard birds by location guides for region-specific species lists.

What Does the Great Cormorant Eat?

The Great Cormorant's diet consists predominantly of fish, which it captures with remarkable skill. It dives from the surface and uses its powerful legs to propel itself underwater, targeting fish ranging from small fry to larger species up to 30 cm in length. Their diet varies seasonally, with a preference for schooling fish like herring and mackerel in coastal areas, and perch or carp in freshwater habitats. They also consume crustaceans and mollusks when available. Foraging occurs throughout the day, with peak activity in the early morning and late afternoon. Their hunting technique is efficient, often involving cooperative strategies when within flocks.

Great Cormorant Behavior and Social Structure

Great Cormorants exhibit complex social behaviors. They are highly gregarious, often seen in large flocks outside of the breeding season, roosting communally in favored spots. During the breeding season, males display elaborate courtship rituals, including posturing and vocalizations to attract mates. They establish territories within colonies, which they defend aggressively. The birds are diurnal, with activity peaking at dawn and dusk. Predators include large birds of prey, such as eagles and hawks, to which they respond with alarm calls and by taking to the air en masse. Their daily routine includes long periods of foraging interspersed with preening and drying their plumage.

Great Cormorant Nesting and Reproduction

Great Cormorants build substantial nests using sticks, seaweed, and other available materials. These nests are typically located on cliffs, trees, or artificial structures near water. They prefer elevated sites that offer a clear view of the surroundings, which helps in predator detection. The female lays 3-5 eggs per clutch, which both parents incubate for about 28-31 days. After hatching, both parents share feeding duties, regurgitating food for the chicks. The young fledge at around 50-60 days old, depending on environmental conditions. Typically, they raise one brood per year, although in favorable conditions, a second brood is possible.

Great Cormorant Sounds and Vocalizations

The Great Cormorant is not known for melodious songs. Instead, it produces guttural, croaking sounds, often described as low grunts or groans, particularly during the breeding season. These vocalizations serve as communication within colonies, especially during pair formation and territorial disputes. Their calls lack the musical quality of songbirds, being more functional than aesthetic. Alarm calls are sharp and urgent, intended to alert others to the presence of predators. During dawn and dusk, colonies can become quite vocal, creating a cacophony of sounds as they settle down or prepare to leave for feeding.

Interesting Facts About the Great Cormorant

1Great Cormorants can dive as deep as 35 meters, showcasing their incredible underwater agility.
2In China, cormorant fishing has been practiced for over a thousand years, where trained birds catch fish for humans.
3The Great Cormorant's plumage is only partially waterproof, which aids in diving but requires regular drying.
4Their eyes have a special nictitating membrane, allowing them to see clearly underwater while hunting.
5Great Cormorants can live up to 25 years in the wild, a testament to their adaptability and resilience.
6While primarily piscivorous, they have been observed eating small mammals and birds when fish are scarce.
7The species has been recorded in fossil records dating back to the Pleistocene, indicating its long-standing presence.

Great Cormorant Conservation Status

The Great Cormorant is classified as Least Concern by the IUCN, with populations generally stable or increasing, particularly in Europe and Asia. However, they face threats from habitat destruction, pollution, and human-wildlife conflict due to their impact on fisheries. Conservation efforts include habitat protection and management of breeding sites. In some regions, population control measures are implemented to mitigate conflicts with fisheries. Historically, the species suffered from persecution and habitat loss, but conservation actions have facilitated recovery in many areas, showcasing successful wildlife management strategies.