Eagles in Illinois

Eagles in Illinois

Eagles are some of the most awe-inspiring birds to watch. These huge animals have a wingspan larger than adult humans and are as tall as children. They soar high in the sky scouting for food with their incredibly vision. Watching eagles hunt is an experience that is hard to forget. There is something surreal seeing such a big creature dive from the sky taking large prey. 

The USA is home to just four species of eagles, and only two of them can be found in Illinois – the Bald Eagle and the Golden Eagle. Read along in this article to know where to see them and learn about their way of life in the Prairie State.

1. Bald Eagle

  • Scientific name: Haliaeetus leucocephalus
  • Life span: 20-30 years
  • Size: 2.5 to 3 feet (0.7 to 0.9 meters)
  • Weight: 6.6 to 13,8 lbs (3 to 6.3 kg)
  • Wingspan: 66 to 96 in (165 to 244 cm)
  • Status: Least Concern

The Bald Eagle is the emblem of the United States of America and the national bird. Majestically soaring high above ground and killing its prey in a spectacular way, this bird is not always majestic, as it also feeds on carrion and steal prey from other birds. The Bald Eagle had a tough time in the 20th century, almost disappearing from the United States but has since made a healthy comeback and is now flourishing in the country it represents.

Living near bodies of water, the Bald Eagle is present in all of the United States from Alaska to Northern Mexico through most of Canada. The plumage is evenly dark brown across the body with a white head and white tail and yellow beak. The name Bald Eagle stems from the old English word piebald meaning “two-colored” and not because their heads are without feathers.

A Bald Eagle in flight close to the ground.


Bald Eagles will sexually mature when they’re 4-5 years old. After spending those years away from the nest they were born in, they return to that area to find a mate. Bald Eagles mate for life. The courtship display is a complicated mix of calls, swoops, chases, cartwheels and other aerial acrobatics. They end up by locking talons and free falling from the sky, separating just before they hit the ground, almost like a close dance.

Bald Eagles start to nest by February hatching their eggs in mid April to start May. Their nests are usually made in tall trees and is built by both the male and the female. The nests consist of a mound of sticks lined with finer materials such as grasses, feathers, cigarette filters and mosses.

The Bald Eagles may reuse their nests their whole life making some of the nests huge, as they expand upon them every season.


The bald eagle is an opportunistic carnivore, with fish comprising over 50% of its diet. A study investigated 20 different habitats of the Bald Eagle and found that 56% of its diet was fish, 28% was birds, 14% was mammals and 2% was other prey. When food availability is scarce, the Bald Eagle turns to scavenging behaviour, eating prey killed by other animals.

When hunting, the Bald Eagle will soar high in the sky, unusually over a body of water to hunt large fish. The Bald Eagle has the ability to see ultra violet light, meaning that its vision is able to see further down in the water than humans, making it easier for the bird to spot fish. Over 100 different species of fish have been identified as prey for the Bald Eagle.

Bald Eagle

When coming down from the sky they can reach up to 100 mph. With such tremendous speed the fish stands no chance of seeing what’s coming, and the eagle’s sharp talons are made for grabbing onto fish. It will drag its prey to the shore to consume it.

When hunting birds, the Bald Eagle uses the same strategy of soaring high above bodies of water looking for waterbirds like grebes, mallards and coots. Sometimes they will swoop down and catch them on the water and other times they will catch them mid-air, which is a spectacular sight!


In the 18th century the population of Bald Eagles in the USA is estimated to be 300,000-500,000 individuals but by the 1950s there were only 412 nesting pairs left in continental USA. Many factors contributed to their decline, and the speed of decline really took off in the 20th century. In the 1920s, it was generally believed that the Bald Eagles were grabbing young lambs from farmers and kidnapping children and thus around 70,000 individuals were shot in that decade, legally and illegally.

During the 20th century the pesticide DDT became extremely popular, but it had a detrimental effect for all bird species in the country. In short, DDT became biomagnified in the food chains, where the Bald Eagle was on top. When DDT enters the bird, it makes their ability to make egg shells extremely bad, making their eggs collapse under the weight of the adult birds when brooding. Thus, the birds were not affected directly but they were unable to reproduce.

The first protection of the species came in 1819 in the Migratory Bird Treaty. In 1940 the Bald and Golden Eagle Protection Act was approved, prohibiting commercial trapping and killing of the birds.

The Protection Act made further restrictions in 1962 and 1972. Also in 1972, DDT was banned in the USA, making the population bounce back. It’s estimated that there are around 300,000 individuals today in the USA.

Where to look for them

As fish make up most of their diet, Bald Eagles are easiest to find near bodies of water. In Illinois they’re most abundant in winter, and the state has more wintering birds than any other continental state, making it great for Bald Eagle spotting. Illinois is believed to have around 200 breeding pairs of birds scattered across the state, but Starved Rock State Park and Matthiessen State Park are the areas with the highest densities of wintering and breeding birds, making them optimal places to go Bald Eagle spotting.

2. Golden Eagle

  • Scientific name: Aquila chrysaetos
  • Life span: 30 years
  • Size: 33 inches (83 cm)
  • Weight: 6.4 to 13.2 lb (2.9 to 6 kg)
  • Wingspan: 70 to 90 in (180 to 230 cm)
  • Status: Least Concern

The Golden Eagle is a large and awe-inspiring raptor with habitats ranging much of the Northern Hemisphere in America, Europe and Asia. They’re mostly dark goldish-brown, hence their name.

Often holds wings in slight V-shape when soaring. Hunts mainly small mammals in remote, open areas from grasslands and steppes to mountainous areas. The Golden Eagle is important in many Native American tribes, and was revered for its courage and strength, and people who possessed their feathers were believed to have been blessed by its being.

Golden Eagle


Like the Bald Eagles, the Golden Eagles mate for life. They also show a similar courtship display with aerial acrobatics. The male will pick up a rock or small stick to drop off mid-air and catch it again. The female takes a clump of dirt or earth to do the same thing. Golden Eagles start to nest around April and often chooses cliffs as their nesting habitat. They will often build more than one nest and reuse them every year. The nests are made with large sticks lined with grass and other soft natural materials.


Unlike the Bald Eagle, the Golden Eagle hunts close to the ground and is strictly a carnivore. It will sit perched in high places looking for its prey. When spotted, it flies above the terrain scaring small mammals like rabbits, hares, ground squirrels, prairie dogs and marmots out of their hiding places making them visible and easy to catch.

Although this method seems effective, studies show that only around 20% of hunting attempts are successful. Like the Bald Eagle and other eagles, they’re extremely dependant on the weather to fly effortlessly, and thus in bad wind conditions they spend up to 85% of the daylight sitting in trees or nests waiting for the wind.



In North America, the Golden Eagles share the same history, albeit in a less extreme degree, as the Bald Eagles, by having seen a steep decline in the 20th century due to hunting and indirect DDT poisoning. Today it is estimated that there are around 30,000 individuals left in the United States with a rather stable or slight decreasing population trend and is present in most states.

Golden eagle in flight

In 1940 the Bald and Golden Eagle Protection Act was approved, prohibiting commercial trapping and killing of the birds. The Protection Act made further restrictions in 1962 and 1972. Also in 1972, DDT was banned in the USA, making the population bounce back.

Where to look for them

The Golden Eagle is a relatively rare bird in Illinois, using the state only as a wintering habitat. It’s often seen in winter along the Mississippi River and at wildlife refuges in southern Illinois. Unlike other eagles, the Golden Eagle doesn’t congregate in groups but are either seen alone or in pairs. When not swooping above open plains, the best place to look for them is in tall trees or on fence posts along the Mississippi River valley, especially in the south.


Though Illinois doesn’t seem to be an avid eagle watching state, it is the state with the highest number of wintering Bald Eagles. While the population of wintering Golden Eagles is much lower, there’s still a good chance of spotting them if you’re near the Mississippi River.

Eagles like the Golden and Bald Eagles are revered and have a long history of reverence in American Indian traditions and religion. Even today in modern USA, the birds are still looked upon with great respect and pride.

Eagles have been hunted because of their perceived threat to livestock for centuries. They have also faced many other dangers like indirect poisoning, trapping and habitat destruction, making some of the species close to extinction during the 20th century. Collisions with cars, buildings and towers are still a large threat to many birds of prey like the Golden and Bald Eagles.

Eagles are fascinating to watch as they float through the air or perch on tree tops. They are often the highlight of a bird watching trip, even if they’re common where they’re spotted.

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