Physical Features of Bald Eagles
Eagles have a beauty and grace fitting their status as our national emblem. As with most birds of prey, the female eagle is larger and heavier than the male. They weigh an average of 12 pounds with a maximum wingspan of seven feet and a body length of nearly three feet. Bald eagles are lighter than they appear. The bulk of an eagle is its feathers; its bones are hollow and much lighter than the bones of mammals.
Adult eagles are easily detected by their brilliant white heads and tail feathers and chocolate brown bodies and wings. They have black talons and yellow eyes, beaks and feet. The majority of the eagles at Wolf Lodge Bay are adults, but you may see several dark, mottled juvenile eagles. Immature eagles do not obtain their adult colors until they are about five years old.
In captivity, bald eagles have a life expectancy of up to 50 years. In their natural environment, the chance of bald eagles reaching such an age is slim because of environmental hazards and stresses. In the wild, almost 80 percent of young eagles die during their first year, and many of the remaining 20 percent die before reaching maturity. Bald eagle productivity is naturally low, as with most other long-lived species. Excessive mortality to these birds is much more serious than in species with higher rates of reproduction.
The eyes of eagles give them a hunting advantage. Eagles’ eyes are three to four times more powerful and sharper than human eyes and contain many times the number of color-sensitive cones. Their eyes are located on the side of the head, giving them a wide field of view. Although they have relatively poor night vision, during the day they can pinpoint their prey in vivid detail from great distances. At Wolf Lodge Bay their eyesight enables them to easily detect floating fish.
Bald eagles have large wings compared to other birds, allowing them to soar and hunt vast areas with a minimum of effort. During migration they can travel 400 to 500 miles a day. While not as quick and maneuverable as other birds, bald eagles have proven themselves to be skillful and agile hunters. Bald eagles have large, sharp talons and strong feet. As they swoop down on prey, their two-inch talons, or claws, easily sink into the flesh of the fish. Once settled on a perch to feed, you may also notice how adept they are at using their hooked beaks to rip the flesh from the fish.