Eagles are present in Illinois, gracing the state’s skies and waterways. These majestic raptors, once facing severe population declines, have made a remarkable comeback, with Illinois becoming a significant wintering ground. Their increasing presence offers unique opportunities for observation.
Eagles in Illinois
The primary eagle species in Illinois is the Bald Eagle, recognized by its distinctive white head, tail, and bright yellow beak and feet in adulthood. These large birds measure 30 to 31 inches in length with wingspans up to 8.5 feet. Immature Bald Eagles appear dark brown with mottled white, developing their iconic white plumage around 4 to 5 years of age. Golden Eagles are also occasionally sighted in Illinois, particularly as rare winter residents along the Mississippi River and in southern Illinois wildlife refuges. They are dark brown with a golden patch on the back of their neck and a wingspan of about seven feet.
Illinois’s Appeal to Eagles
Illinois provides winter habitat for eagles, primarily due to its major rivers like the Mississippi and Illinois. These waterways offer a consistent food supply; fish comprise over 50% of a Bald Eagle’s diet, with gizzard shad being a primary source. When fish are scarce, eagles also consume small birds, mammals, and carrion. Tall trees along riverbanks offer ideal roosting and nesting sites, providing shelter and elevated perches for hunting. Areas with reduced human disturbance also contribute to a secure environment for these birds.
Where and When to See Them
The best time to observe eagles in Illinois is during winter, from December through March, with peak viewing in January and February. Thousands of Bald Eagles migrate south from northern breeding grounds to Illinois, seeking open water for fishing. Prime viewing locations include areas near locks and dams along the Mississippi and Illinois Rivers, where water remains unfrozen. Notable spots for eagle watching include Pere Marquette State Park, Starved Rock State Park, Mississippi Palisades State Park, and locations in Alton, Grafton, and Quincy. Many state parks and towns host special eagle-watching events during the winter season.
When observing eagles, practice ethical viewing to minimize disturbance. Maintain a respectful distance, ideally at least 330 feet from nests. Use binoculars or spotting scopes for close-up views without encroaching on their space. Avoid loud noises, sudden movements, and refrain from attempting to make eagles fly, as this causes undue stress. Patience is important for successful eagle watching.
The Eagle Comeback Story
The Bald Eagle experienced a significant population decline in the 20th century due to habitat loss, illegal hunting, and widespread use of the pesticide DDT. When ingested through prey, DDT caused eggshells to become thin and fragile, leading to reproductive failure. By 1963, only an estimated 417 nesting pairs remained in the contiguous United States.
The 1972 ban of DDT in the United States was an important step in their recovery. Protection also came from the Endangered Species Act of 1973, which listed the Bald Eagle as endangered, and the Bald and Golden Eagle Protection Act (1940, amended 1962). These acts prohibited the “taking,” possession, or disturbance of eagles, their parts, nests, or eggs. Through conservation efforts, including habitat preservation and legal protections, the Bald Eagle population rebounded, leading to its delisting from the Endangered Species Act in 2007. The species remains protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act.