About Bald Eagles
Bald Eagles are fish, or sea eagles, so called because they’re skilled at catching fish, as well as sea birds and small land mammals. (They also feed on carrion and may steal prey from other raptors.) While the species is seen almost everywhere in Canada, the United States, and northern Mexico, larger populations congregate in coastal areas.
Most Bald Eagles breed in the northern part of their range, building enormous nests in areas where food is plentiful. They are long-lived birds, surviving up to fifty years in captivity, but less in the wild where they face many more threats.
Description of Bald Eagles
Adult Bald Eagles can grow to about a metre (three feet) in length with a wingspan of twice that. The female is larger and can weigh as much as nearly 8 kilograms (15 pounds). Males and females look alike with an evenly brown body, appearing almost black from a distance, and a white head and tail. The eyes, hooked beak, legs, and feet are yellow.
Immature birds of this species are a mottled brown, with more patches of white appearing as the young eagle matures. Young birds have yellow feet like adults, but their beaks are grayish and the eyes are brown. Because of their brown coloring, immature Bald Eagles may be mistaken for Golden Eagles—distinguishing features include feathered legs on the Golden Eagle and mottled white colouring on the young Bald Eagle.
Bald Eagle History
The only eagle whose range is limited to North America, the Bald Eagle is Canada’s largest bird of prey. (In the United States, the California Condor is larger.) Once much more common than it is today, Haliaeetus leucocephalus has suffered major setbacks since the arrival of European settlers. Killed by hunters, trappers, farmers, pesticides, and other pressures, the species faced extinction in the mid-twentieth century but has since recovered significantly:
- 1600 – About 500,000 Bald Eagles are thought to have flown over North America.
- 1782 – The Bald Eagle became the national emblem of the United States.
- 1800 – The species went into marked decline as settlers cleared forest, plowed prairie, and enthusiastically shot and trapped eagles.
- 1940 – A second wave of deaths was caused by indiscriminate use of agricultural pesticides, particularly DDT.
- 1960 – The species was near extinction.
- 1967 – The Bald Eagle was listed as endangered.
- 1972 – The US government banned DDT, a pesticide that caused low reproductive rates in raptors.
- 1973 – The American Endangered Species Act made it illegal to harm a Bald Eagle.
- 1995 – Populations had recovered sufficiently to reclassify the bird as threatened.
- 2007 – Delisting: no longer threatened, the species remained protected by the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act
- Today – The population of Bald Eagles is more than 100,000.
Fascinating Facts about Bald Eagles
A Bald Eagle circling overhead or perched high in a tree is breathtaking by itself, but there are other fascinating things about these large birds:
- The species has very keen eyesight, with a range three to four times that of human sight.
- One of the largest Bald Eagle nests ever found reached a size of eight square metres (about 86 square feet).
- The species name leucocephalus means white-headed. Similarly, in the common name, bald used to mean white, as in piebald, so both names aptly describe the bird.
- Bald Eagles can lift off and fly with prey that is half their weight. When a fish or sea bird is two heavy, the eagle sometimes uses its wings to row itself to shore, dragging the prey with it.
- Bald Eagles can fly up to 10,000 feet and can remain aloft for long periods, riding thermal currents.
Sources:
“Bald Eagle.” Cornell Lab of Ornithology All About Birds.
“Bald Eagle: The USA’s National Symbol” American Eagle Foundation
“Bird Fact Sheets: Bald Eagle.” Canadian Wildlife Service and Canadian Wildlife Federation Hinterland Who’s Who.
Birds of North America Kaufman, Kenn. New York: Houghton Mifflin; 2000
 |
 |
