Bird of the Month: Great Cormorant

Posted on 22 February, 2024 by Anna

Welcome to Bird of the month, a partnership between Connecting Country and BirdLife Castlemaine District. Each month we’re taking a close look at one special local bird species. We’re excited to join forces to deliver you a different bird each month, seasonally adjusted, and welcome suggestions from the community. We are blessed to have the brilliant Jane Rusden and Damian Kelly from BirdLife Castlemaine District writing about our next bird of the month, accompanied by Janes’s stunning photos.

Great Cormorant (Phalacrocorax carbo)

While sitting in the deep shade of Castlemaine Botanical Gardens, nature journaling with BirdLife Castlemaine District, we witnessed a Great Cormorant diving underwater fishing. Somehow it managed to swallow, with considerable effort, a huge silver fish which glistened in the morning sun. After the swollen bulge in its neck deflated as the massive fish went down its gullet, the Great Cormorant had a swish of its face and a bit of a bath, before perching on the much-loved tree that hangs well over the water from the island in Lake Johanna. After a bit of a preen, it set about drying its wings and digesting its huge meal.

Great Cormorant drying its wings in a typical pose for the species. Bird feathers are structured to be waterproof and trap air, but diving birds have a more open structure because trapped air would be like trying to dive with floaties on … very difficult. As a consequence, the Great Cormorant gets soaking wet and needs to dry out after a fishing session. Photo by Jane Rusden.

The Great Cormorant is a true cosmopolitan species. You can find it in the Botanic Gardens in Castlemaine as well as across the world. It is the most widespread cormorant and can be found over much of Europe as well as China, Japan, Africa, India, America, New Zealand and parts of South-east Asia. Up to 6 subspecies are recognised. Overseas birds tend to have more white on the face than Australian birds.

As a very adaptable species, it can be seen both along the coast as well as inland wherever there are rivers or large water bodies. Banding studies in Australia show that some birds are sedentary, but more than half were later recorded a long way from their original location. Birds have been recorded travelling from NSW to Western Australia and even as far as Macquarie Island and Lord Howe Island.

Interestingly, overseas in Europe and America it is largely associated with coastal regions and estuaries. However, in Australia it is primarily a freshwater bird. Diet consists mainly of fish, crustaceans, frogs and large insects. Fish are usually caught by diving, with mainly shallow dives of 1-3 metres and mostly less than 1 minute under water. The deepest dive recorded has been 9.5 metres.

A Little Pied Cormorant (left) and a Great Cormorant (right) perched, at Lake Johanna. Notice the beautiful teal colour of the Great Cormorant’s eye. Photo by Jane Rusden.

Great Cormorants are sociable birds that breed and travel in groups. Breeding is usually in large colonies up to 2000 birds, although one colony at Lake Menindee in NSW numbered around 20,000 birds. Breeding tends to be erratic, especially inland where it depends on water levels. Nests are open, flat platforms made of sticks, twigs, plant material and debris. Usually 3-5 eggs are laid and both parents incubate and feed the young.

Their range overlaps with other Australian cormorants but usually it is easy to separate them as only the Little Black Cormorant is similar, although it lacks any yellow on the face area.