Despite the name, the bald eagle is not actually “bald.” The term comes from the word “piebald,” which describes something that is spotty or patchy, since the white feathers on the eagle’s head and tail are in sharp contrast to the rest of its darker body. Both female and male adult eagles have the same dark brown colouring. Young eagles take four to six years to develop the characteristic white plumage. Before this happens, they can be mistaken for other birds, such as the osprey, another large fish-catching raptor.
As Canada’s largest bird of prey, the bald eagle is built to hunt and scavenge. It has a giant yellow beak and oversized talons, and its feet are equipped with small spikes called spicules, which are ideal for attacking and grasping its prey, especially slippery fish. With a wingspan that can exceed two metres, it can soar high above the ground looking for food. It also has incredible eyesight and is able to see four to seven times farther than a human can.
Habitat and behaviour
The Latin genus name Haliaeetus, meaning “sea eagle,” is appropriate, since the bald eagle usually chooses to breed and build its nest in trees near rivers, lakes and sea coasts. Living by a body of water gives the eagle easy access to its preferred diet of fish. When fish are in short supply, the bald eagle will eat almost anything, including waterfowl, roadkill and even small deer.
During the breeding season, when food for the young must be collected near the nest, the eagle largely eats fish or other small, easy-to-carry prey such as small rodents. In winter, the bald eagle generally scavenges for food rather than hunting for it. Most of its prey at this time of year is already wounded, sick or dying from encounters with other animals or hunters. With fish, it usually eats carcasses that have washed ashore or have passed through hydropower turbines. It often steals kills from other birds, though young eagles are more likely to pirate food than are the adults.
The bald eagle is thought to mate for life. During the courtship ritual, the male and female “dance” together while flying high in the air, locking talons, calling to each other and engaging in a series of acrobatics, including cartwheels, roller-coaster-like dives and chases. The actual mating takes place on a branch or in a nest. The female typically lays two eggs. In times of food shortages, nearly 50 percent of young bald eagles are killed by a bigger sibling during the first year.
The bald eagle is one of two North American eagle species — the other is the golden eagle — and is found mainly on this continent.
Although the bald eagle in Canada prefers the Pacific coast of British Columbia, it is also found in the Prairie provinces and northwestern Ontario, and there have been sightings of small groups in Cape Breton and on the coast of Newfoundland. The bald eagle ranges as far north as Alaska and populates more than half of the United States and portions of Mexico. It is especially abundant from Florida to California.
The bald eagle has no natural predators, being at the top of its food chain, a position further aided by building its nest high in the trees, where predators such as wolves, wolverines and bears can’t reach it. Yet human hunting and DDT-tainted fish once almost depleted the bald eagle population in eastern North America. However, since DDT was banned for agricultural use in Canada in 1970 and restrictions were put in place to protect the bald eagle’s habitat, its range is expanding and its future is more secure.