Necropsy results from the dead bald eagle found near Lower McDonald Creek in February in Glacier National Park have determined that the bird died of lead poisoning. Park biologists sent the carcass to the National Wildlife Health Center in Madison, Wisconsin, for further evaluation after the assessment that was done initially showed no evidence of gunshot, stray bullet or other obvious signs of trauma.
Bald eagles are protected by the 1940 Bald and Golden Eagle Protection Act, which prohibits anyone from harming them, that includes shooting, poisoning, capturing and other numbers of activities. This is not the first eagle found in the West Glacier area that died from lead poisoning. In April 2012, park staff found a sub-adult golden eagle carcass in the same vicinity. A necropsy determined that lead poisoning was the cause of death. A similar case was discovered just recently in Yellowstone National Park.
The necropsy for the eagle discovered in February found the immature female bald eagle was emaciated. The gall bladder of the eagle was distended and filled with green bile that is vicious and is typical in birds that are killed by lead poisoning. Lead is a naturally occurring heavy metal that has been used in the manufacturing of lead fishing sinkers and hunting ammunition. Although both lead fishing tackle and hunting are not permitted in Glacier, bald eagles do not spend their lives within the boundaries of the park where they are protected, they can be exposed to lead outside of the park.
Eagles are top avian predators, but they are also known scavengers. Eagles will feed on the dead rodents that are left in fields or pastures after being shot, and on gut piles left by hunters in the fall. If the hunter used lead ammunition, small lead bullet fragments are usually present in the carcass. Non-lead ammunition is safer for wildlife.
Hunters who opt for lead ammunition can reduce impacts to wildlife by removing the gut piles from the field and disposing of them in plastic garbage bags. When an eagle eats on enough of these carcasses or gut piles, lead can accumulate in the bird's body in a process called bioaccumulation. High lead levels can cause significant damage to the brain and the nervous system of the Eagles, making it difficult for them to eat and to hunt. Eagles suffering from lead poisoning are often emaciated because of their inability to hunt, and they eventually end up dying.
If you happen to see any sick or injured wildlife, or any animal acting strangely in Glacier National Park, you can report your sightings to a park employee and take photos or videos from a safe distance. Do not approach or even attempt to capture the wildlife on your own.
