double-crested cormorant

Phalacrocorax auritus

double-crested cormorant

Double-crested cormorant, photographed at Green Cay Nature Center, Boynton Beach, Palm Beach County, in November 2016.

If you're a fish, the double-crested cormorant, Phalacrocorax auritus, isn't a bird you want to see swimming about. You could be his next meal.

Double-crested cormorants have a mostly seafood diet, and when it comes to fish, they're not picky eaters. More than 250 species of fish are on their menu. And they're very good at catching them. Find any sizeable body of water, fresh or salt, and there's a good chance you'll find them hanging about.

There are six species of cormorants native to North America. The double-crested cormorant is the most common of the six, with a range that covers a good chunk of the continent. They are year-round residents of Florida's peninsula and winter residents of the Panhandle and adjacent Gulf Coast states. Cormorant populations can be found along the Pacific Coast into Alaska's Aleutian Islands and along the Atlantic to the St. Lawrence River and into the Great Lakes. Migratory cormorants spend summer in the northern Great Plains and Rockies of the United States, and north into Canada. They can be seen pretty much anywhere in the Lower 48 during migration.

They are large birds, gray-black, with long necks and tails. The most distinguishing features are the orange face, long orange bill with a sharp hook at the end. They also have dazzling tourquoise eyes. They're similar in appearance to anhingas, and share a lot of the same habitats, and even share a common name, the water turkey. But the cormorant's orange face and hooked bill easily separate the two. The odd thing is that despite their similarities, cormorants and anhingas are not related. Their namesake "crests" are whisps of white or black feathers visible on the bird only during mating season.

As previously noted, cormorants' main diet is fish, although they will eat insects, amphibians and crustaceans. They hunt while swimming under water, catching prey with their bills. Like anhingas, cormorants lack oils common in other water birds that repel water from their feathers. They're often spotted perched with their wings spread, using the sun and wind to dry out. This lack of oils actually is an advantage, allowing these birds to swim lower in the water. Cormorants are also heavier boned than most birds, which also helps them dive after prey.

Cormorants are usually found near water, both in coastal areas and well inland along rivers, lakes and ponds. They can, however, fly long distances for food. They nest in tree islands, forming colonies, but also in rocks and on the ground. Both males and females help build the nest, with the male gathering most of the material, and the female doing most of the construction. They use mostly twigs, but will include the odd piece of trash and even parts of dead birds. Cormorants are known to "borrow" twigs from a neighboring, unguarded nest. The inside of the nest is lined with grass.

Cormorant can have one or two broods a year, with clutches of one to seven eggs each. The eggs require between 25 and 28 days of incubation. Both parents share incubation duties and feeding their offspring. Young cormorants fledge in about five weeks and are sexually mature in three years.

Cormorant numbers dwindled seriously, as they were killed off in the mistaken belief that they were damaging fishing grounds. Pesticides such as DDT, now banned, also took a toll. Double-crested cormorants are protected under the Migratory Bird Treaty Act. The population has recovered substantially, exploding in some areas, particularly in the Great Lakes Region.

The U.S. Fish and Wildlife Service can issue permits to kill cormorants and has taken steps to do so, particularly for fish farmers that have seen their "crops" affected by the birds.

Double-crested cormorants are members of Phalacrocoracide, a family of birds that include frigatebirds and boobies.

Green Cay Nature Center

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Published by Wild South Florida, PO Box 7241, Delray Beach, FL 33482.

Photographs by David Sedore. Photographs are property of the publishers and may not be used without permission.