By Peter Roos
Double-Crested Cormorants The 30-foot Ficus tree in our backyard has recently become the evening perch for four young, double-crested cormorants. These amazing birds are found in coastal areas, and near rivers and streams from Florida to Alaska’s Aleutian Islands. The four arrive within minutes of one another as the sun is setting and always seem to land on the same long thin branch as they stood on the night before.
At sunrise, they head off for a day of swimming and fishing. Ducks and other water birds have more preen oil in and on their wings, which helps them shed water. Cormorants’ feathers get saturated with water quickly, allowing them to submerge more easily to chase their prey. Underwater, their feet propel them like flippers, their wings too sometimes. Their diet includes a very wide variety of fish, seafood, and some plant material. Cormorants are often seen drying their feathers in the breeze.
When mature, they nest in colonies, sometimes mixed with by splashing with wings, swimming in zigzags, diving and bringing up pieces of weeds. At the nest site, the male displays by crouching and vibrating wings while calling. Nest sites are near water on cliff ledge, on ground on an island, or at any height in trees.
Nests are built mostly by females, with materials brought by male, a platform of sticks and debris, lined with finer materials. They usually first breed at 3 years of age. They lay 1-7, most often 3-4 bluish-white eggs which are tended by both parents until they hatch in about a month. Both parents feed the hatchlings who begin to wander from ground nests at 3-4 weeks and begin to fly two weeks later. At 9-10 weeks they are generally independent.
In China and Indonesia, as a traditional fishing method, a snare is tied around a tame cormorant’s neck to stop it from swallowing bigger fish, which the fisherman gets. This is now mostly a tourism activity. (Info thanks to Audubon)