Great Cormorant: A Master Fisher Bird

About Great Cormorant

Great Cormorant (Phalacrocorax carbo) is a large, versatile bird species belonging to the Phalacrocoracidae family. Its closest relatives include other cormorant species and shags. With its distinctive dark plumage, long neck, and hooked bill, Great Cormorant is an easily identifiable bird in the field.

Great Cormorant has a wide distribution that encompasses Europe, Asia, Africa, and Australia. They inhabit a variety of aquatic environments, such as coastal waters, estuaries, lakes, and rivers. These birds are highly adaptable and can thrive in both freshwater and marine ecosystems.

In history, Great Cormorants have had a complex relationship with humans. In some regions, these birds have been admired for their fishing skills and used in traditional cormorant fishing practices, while in other areas, they have been seen as competitors for fish resources. The role of Great Cormorant in the ecosystem is significant, as they help control fish populations and maintain the balance within their aquatic habitats. A fun fact about these birds is that in ancient Chinese culture, cormorant fishing has been practiced for over a thousand years, showcasing the longstanding connection between humans and these skillful birds.

Cormorant Fishing

Cormorant fishing is an ancient and traditional fishing method practiced in various parts of the world, most notably in China and Japan. It involves the use of trained cormorants, which are large aquatic birds, to catch fish.

Fishermen train the cormorants to dive into the water, catch fish in their beaks, and bring them back to the boat. To prevent the birds from swallowing the fish, a snare or ring is often placed around the bird’s neck, allowing it to eat smaller fish but not the larger ones targeted by the fishermen. Once the cormorant has caught a fish, the fisherman retrieves the bird and removes the fish from its beak.

This practice has been in use for over a thousand years and is considered a cultural tradition in the areas where it is practiced. In some places, it has become a popular tourist attraction, showcasing the unique relationship between the fishermen and their avian partners.

Great Cormorant Details

• Size: Length 80-100 cm / 31-39 in, wingspan 121-160 cm / 47-63 in
• Mass: 1.5-5 kg / 3.3-11 lb
• Color: Black feathers, white thigh patch, yellow bill
• Diet: Fish, eels, and other small aquatic animals
• Distribution: Found in coastal areas and inland waterways across Europe, Asia, Africa, and Australia
• Natural habitat: Marine and freshwater habitats
• Family: Phalacrocoracidae (Cormorants)
• Closest relative: Japanese Cormorant (Phalacrocorax capillatus)
• Conservation status: Least Concern
• Oldest fossils date: Late Oligocene to Early Miocene (about 25-23 million years ago)

Physical Characteristics

Great Cormorant is a sizable bird with a body length of approximately 80-100 cm / 31-39 inches and a wingspan ranging from 130-160 cm / 51-63 inches. Their weight can vary between 1.5-3 kg / 3.3-6.6 lbs, making them one of the largest cormorant species. Their dark plumage is primarily black or dark brown, with a greenish or purplish sheen that becomes more pronounced during the breeding season.

One of the distinguishing features of Great Cormorant is the white patch on their cheeks and throat, which is more prominent in adults. Their hooked bill is well-suited for catching fish, while their webbed feet enable them to be efficient swimmers. During the breeding season, adult Great Cormorants develop a white patch on their flanks and a small crest on their heads.

Sexual dimorphism in Great Cormorants is not very pronounced. Males and females have similar coloration and features, but males tend to be slightly larger in size. Their similar appearance can make it challenging to differentiate between the sexes in the field.

Habitat & Distribution

Great Cormorant is a highly adaptable bird species that can be found in various aquatic habitats. They are known to inhabit coastal waters, estuaries, rivers, lakes, and even reservoirs. Their preference for these environments is closely linked to the availability of fish, their primary food source.

The distribution of Great Cormorant spans across continents, covering Europe, Asia, Africa, and Australia. They have a particularly strong presence in the Northern Hemisphere, where they can be found virtually in every country.

Some populations of Great Cormorant are sedentary, remaining in their chosen habitats year-round, while others exhibit migratory behavior. In colder regions, these birds may migrate to milder climates during the winter months to avoid ice-covered waters, which limit their ability to catch fish. Their adaptability and wide range of habitats contribute to the extensive distribution of Great Cormorant around the world.

Diet & Feeding Behavior

Great Cormorants are primarily piscivorous, with their diet consisting mainly of fish. They are known to consume a wide variety of fish species, including eels, perch, and salmon, depending on the availability of prey in their habitats. Occasionally, they may also feed on amphibians, crustaceans, and mollusks.

Their feeding behavior is characterized by expert diving and swimming skills. Great Cormorants are capable of diving to depths of up to 12 meters / 39 feet and can stay submerged for around 30 seconds to 1 minute. They use their powerful webbed feet to propel themselves underwater while pursuing fish, which they catch using their sharp, hooked bills.

An interesting aspect of Great Cormorant’s feeding behavior is their habit of swallowing their prey whole, often headfirst. After catching a fish, they typically surface and adjust the fish’s position in their bill before gulping it down. In some instances, these birds have been observed spreading their wings to dry them after diving, a behavior commonly associated with cormorants and a sign of their unique adaptations to aquatic environments.

Breeding & Nesting Habits

Great Cormorants exhibit fascinating breeding and nesting behaviors. Their breeding season varies depending on the geographical location, but it generally occurs between April and August in the Northern Hemisphere. These birds establish nesting colonies, often on cliffs, rocky islands, or in trees close to their aquatic feeding grounds.

During the breeding season, Great Cormorants engage in elaborate courtship displays, which include posturing, vocalizations, and the presentation of nesting materials. Once a pair bond is formed, the male and female work together to construct their nest. The nest is made from sticks, seaweed, and other vegetation, forming a platform for the eggs and chicks.

Female Great Cormorants typically lay 3 to 5 eggs per clutch, with both parents sharing incubation duties over a period of 27-31 days. After the chicks hatch, both parents continue to care for them, providing food and protection. The chicks fledge at around 50 days of age, but they may continue to depend on their parents for several weeks after fledging. In some cases, Great Cormorants have been known to breed cooperatively, with multiple birds contributing to the care of a single brood.

Conservation Status & Threats

Great Cormorant is currently listed as a species of Least Concern on the IUCN Red List, indicating that their global population is relatively stable. However, local populations may still face threats due to habitat loss, pollution, and human-wildlife conflict. In some areas, these birds are considered a nuisance by commercial fishers who perceive them as competitors for fish resources, leading to attempts to control their numbers.

A study conducted in the United Kingdom highlighted the potential impact of wind farms on Great Cormorant populations, as the development of offshore wind energy installations can lead to habitat loss and disturbance. Addressing these threats is essential for the long-term conservation of Great Cormorant populations.

Conservation efforts for Great Cormorant include habitat protection, monitoring of population trends, and efforts to mitigate human-wildlife conflict. Educating the public about the ecological role of these birds and promoting responsible fisheries management can help reduce negative perceptions and foster a more harmonious coexistence between humans and Great Cormorants, but, generally, as long as there is fish, these master fishers will not be in danger.

Conclusion

Obviously, Great Cormorant is an impressive bird species with remarkable adaptations for an aquatic lifestyle. Found across a vast range of habitats, from coastal waters to inland rivers and lakes, these birds have a wide distribution that spans Europe, Asia, Africa, and Australia. Their expert diving and fishing skills make them efficient predators, playing a crucial role in maintaining the balance of their ecosystems.

While the conservation status of Great Cormorant is currently listed as Least Concern, it is vital to address the threats they face, such as habitat loss, pollution, and human-wildlife conflicts. By supporting conservation efforts and promoting responsible fisheries management, we can help ensure the long-term survival of these fascinating birds and preserve the rich biodiversity of their aquatic habitats. The ancient practice of cormorant fishing in China serves as a reminder of the intricate relationship between humans and Great Cormorants, and the importance of coexisting harmoniously with these captivating birds.