South Dakota Bald Eagle Awareness Days         Bald Eagle Awareness Days
 
Bald Eagle Biology

Click to enlargeScientific Name: Haliaeetus leucocephalus; means white-headed sea eagle.

Life Span: May live up to 45 years, but many do not survive their first year.

Measurements: The bald eagle weighs 6-14 pounds and has a wingspread of 7-8 feet. Females are 34-43 inches long, compared to males, which are 30-35 inches in length.

Eyesight: Resolving power is six to eight times greater than humans.

Range: Because of extensive recovery activities, including banning of certain pesticides in the U.S., the bald eagle has returned to much of its historical range in North America. Several pairs now nest in South Dakota. Bald eagles move south for the winter to find open water, abundant food, and protective cover for night roosting. South Dakota's wintering bald eagles congregate mostly on the open water below Missouri River dams. Here they find fish and waterfowl to eat and forest cover for protection against winter winds and low temperatures.

Habitat: Bald eagles usually build their nests in tall trees near water source. During the winter, bald eagles will also concentrate near downstream areas of Missouri River dams where they roost in remnant cottonwood forests that provide protection from cold winds.

Coloration: Adult has a rich chocolate brown body with white head and tail. Birds are four to six years old before they attain this plumage. The beak, feet, and eyes are yellow.Immature bald eagles have a rich chocolate brown body, head and tail. Undersides of the wings are spotted with white. Feet and beak are yellow; eyes are brown.

Diet: Fish make up 60-90% of their diet. Bald eagles will eat live or dead fish, waterfowl and mammals. Their habit of eating carrion (remains of dead animals) makes them vulnerable to poisoning from illegal lacing of animal carcasses for predator control.

The Nest: Also called eyrie or aerie. Consists of a large mass of branches, usually next to the trunk of a tree and typically near water. Nests are often reused year after year. They may reach 12 feet in height, measure more than 8 feet across, and weigh several hundred pounds. Clutch size is one to three eggs, which both parents incubate for about five weeks.

Pair Bond: Adults usually mate for life. The pair bond is maintained with impressive courtship displays, where the pair locks talons in mid-air and somersaults downward. Both parents incubate eggs and care for nestlings. The pair may also hunt together to tire their prey or to steal fish from ospreys. Bald eagles will also harass vultures to force them to disgorge food.

South Dakota's Breeding Population: After bald eagles received protection, the first successful nest in more than a century was located at Karly Mundt National Wildlife Refuge in 1993. Since then, the number of breeding pairs has dramatically increased in the state. In 2015, the estimated number of active nests was between 140-150 in South Dakota.

Protection Status: The bald eagle is protected under several federal laws, including the Migratory Bird Treaty Act and the Bald Eagle Protection Act. Recently, the bald eagle was removed from the state list of threatened birds due to the large increase of nesting pairs.

 Bald Eagle Awareness Days

 Watching Eagles

 Links

 Educational Activities

Download an eagle brochure (PDF file) by clicking here. Brochures can be obtained from the South Dakota Department of Game, Fish & Parks at 523 East Capitol Avenue in Pierre, South Dakota 57501.  If you have questions or comments, email or call the South Dakota Department of Game, Fish and Parks at (605) 773-4229.