They found the bird Tuesday morning at a ramp on I-55 at Cass Avenue in Darien, Ill. IDOT crews blocked traffic while waiting for Animal Care and Control. The injured bird was taken to Willowbrook Wildlife Facility in Glen Ellyn, which is part of the DuPage Forest Preserve, where it died.
Originally, staff at the wildlife center thought the eagle had been hit by a vehicle, but according to a release, they now believe the eagle "might have perished from West Nile virus and that its visible injuries were the result of it being on the ground and unable to fly for some time."
A thorough necropsy will be conducted at the University of Illinois, according to the DuPage County Forest Preserves.
The eagle is the same one that was brought into Willowbrook in February 2014 after it was shot in Oak Lawn. It was treated for a broken wing and released at that time.
"It's an endangered species and it's our responsibility to try and protect it," one IDOT worker said.
PHOTOS: Injured bald eagle rescued along I-55