Bald Eagle
INTRODUCTION
Designated as the national bird of the United States in 1782, the bald eagle nested throughout the nation. Today, it is classified as a Federally threatened species in the lower 48 states. Biologists believe that a loss of wetland habitat caused the drastic decline of the bald eagle in Indiana. The use of industrial pesticides in the 1950s and 1960s caused the bald eagle population to slip to an all-time low. Eagles absorbed these toxic chemicals through the fish that they consumed. When governmental officials finally banned the use of these destructive chemicals, the bald eagle began the long journey down the road to recovery.
GENERAL CHARACTERISTICS
The adult bald eagle is named for its white or bald (the old English word balde meaning white) head. The rest of the bird’s feathering is dark brown with the exception of the tail feathers which are white. Males and females are identical in color. Immature bald eagles are dark brown with some blotches of white under the wings and on the body. As the bird reaches maturity in four or five years, this mottling disappears. The bill of young birds is brownish, and the feet are yellow. Adult birds have bright yellow beaks, eyes, and feet. The body of an adult eagle is about 3 to 3 1/2 feet in length, and the wingspan is 6 to 7 1/2 feet. Males weigh eight to nine pounds; while females weigh 10 to 14 pounds. Young eagles leave the nest or “fledge” at 11 to 12 weeks of age. Adult eagles do not begin to nest until they are four or five years old. Eagles mate for life and return each year to the same location to nest and breed, selecting nest sites close to where they were raised as young. The life span of a bald eagle is quite long, living up to 48 years in captivity and 21 years in the wild. Bald eagles may fly up to 40 mph during normal flight, but they can reach speeds of 100 when diving for prey.
HABITAT
Bald eagles nested in Indiana until the 1890s. A small population still winters in the state from November through March. Wintering eagles are found mostly along major rivers and large, open bodies of water, such as Monroe and Patoka reservoirs. These open bodies of water supply ample space for the birds to forage. Wintering eagles prefer large trees along these bodies of water for daytime perches. At night, large trees in sheltered valleys and ravines are preferred for roosting, and it is not uncommon for eagles to roost in small groups during the winter months. Midwinter bald eagle surveys conducted since 1979 have shown a dramatic increase in wintering eagles in the state.
FOOD HABITS
The primary diet for bald eagles is fish, which are taken near the water’s surface. Fish are usually carried to a tree or perch and consumed. Eagles also take waterfowl, rabbits, squirrels and other small mammals. Most eagles consume animals weighing up to one pound. Eagles have excellent eyesight and can locate prey up to two miles away.
RESTORATION EFFORTS
In 1985, the Indiana Nongame and Endangered Wildlife Program began the Bald Eagle Reintroduction Project. Seventy-three eaglets (seven to eight weeks of age) were obtained from Wisconsin and Alaska during 1985 through 1989 and brought to Indiana. They were placed in a 25 foot tower, consisting of a series of five cages, located in a secluded bay on Lake Monroe. Each cage contained an artificial nest and housed up to three birds. The birds were monitored and fed daily until they were old enough to fly at 11 to 12 weeks of age. The process of raising a young eagle and releasing it back into the wild is called “hacking.” The bald eagles hacked in this project are now at breeding age. The first successful nesting occurred in 1991, and a dozen nesting areas were established in Indiana by the mid 1990s. Most of the eagles are Indiana-released birds. Most nests are located in south central Indiana and are found on larger reservoirs and along the Wabash and White River.
