Double-Crested Cormorant: Fast Facts

Corbis

Double-crested cormorants are dramatic, large aquatic birds with shiny black and bronze plumage. They don't have waterproof feathers like most aquatic birds and need to perch on rocks, sandbars, pilings, wires, trees or docks to dry off.

Habits and Habitat

Double-crested cormorants occupy many water habitats across North America, including coastlines, estuaries, lakes and ponds. Most spend winter in the southern United States, but many nest on the shores of the Great Lakes in spring and summer.

During the breeding season, cormorants are monogamous and live in large, social colonies. Cormorant couples work together raise their young, from building a nest and incubating the eggs to feeding chicks once they have hatched.

Cormorants are avid recyclers. They will sometimes revamp an old nest rather than start a new one from scratch. And when they find pieces of useful junk, like old bits of rope, net, or plastic, they will often incorporate them into their nests.

Presqu'ile Provincial Park in Ontario is home to the largest and most diverse bird colonies in the Great Lakes region. The park is an important staging area for many shorebirds, including Double-crested cormorants, and is recognized internationally as an Important Bird Area.

Prey

In the Great Lakes, the cormorants are voracious predators of the invasive round goby, a Eurasian fish that is causing great ecological damage. They also consume large numbers of alewives, another invasive species, as well as non-native sticklebacks and sea lampreys.

Cormorants help create nesting sites for Blue-herons, who like to nest in trees without leaves.

Calls for Culling

These skillful fishing birds are viewed by some anglers as competitors, leading powerful lobby groups, including the Ontario Federation of Anglers and Hunters, to pressure the Ontario government to cull them.

Concerns have also been voiced that cormorants eat too many fish or damage trees. None of the trees on the islands in Presqu'ile Provincial Park is endangered or of special conservation concern, and scientific research has repeatedly shown that cormorants have no substantial negative impact on fish populations.

Cruel Killing

Even though the park is a sanctuary for birds and a major destination for birdwatchers, the Ontario government killed more than 10,000 cormorants on High Bluff and Gull Islands in Presqu'ile Provincial Park from 2003 to 2006.

The government shoots the cormorants during the nesting season as they incubate their eggs. Observers have seen the corpses of shot cormorants hanging from nests while their live partners stand by helplessly. Sometimes chicks hatch next to their parents' dead bodies, and then starve to death. Observers have reported that many cormorants are not killed immediately by the rifle shots and die slowly by bleeding or drowning.

How to Help

HSI Canada works with Cormorant Defenders International to help protect cormorants from the cruel culls. To learn more about the struggle to protect the Double-crested cormorant and how you can help, visit Cormorant Defenders International.