"We lost yet another golden eagle to lead poisoning yesterday," said Brooke Tanner, founder and executive director, Wild Skies Raptor Center, Potomac, Mt. "It happens every winter after the snow settles. Prey is harder to find and they must scavenge to survive."
After a weakened eagle is found and brought to Tanner or other raptor rehabilitation facilities, the birds are given chelation therapy to bind the lead in their systems and hopefully allow the lead to pass through. Success varies, depending on the condition of the eagle, said Tanner.
In the last six weeks of 2022 Wild Skies had admitted five eagles, all with elevated levels of blood in their system. Lead is a neurotoxin that can affect all the systems in the body causing difficulty breathing, digesting, weakness, and anemia.
Eagles are opportunistic feeders, known to scavenge and take wounded animals. Since 2000, Raptor View Research Institute, Missoula, Mt, has analyzed blood from over 250 migrating Golden Eagles and have found that nearly half of the sampled eagles had elevated blood-lead levels.
"Eagles can tolerate up to 0.1 ppm of lead," according to Mike McTee, Wildlife Researcher, MPG Ranch, Florence, Mt in his book "Wild Wings". "For comparison, take a piece of lead the size of a grain of salt, and shave off one third of the grain. Dissolve that grain into one liter of blood and it's twice the threshold for humans, who are roughly ten times the size of a 10-14 pound eagle."
"The average concentration we see (in the Raptor View studies), if that was found in a child, their doctor would be really worried," said McTee.
"The last lead bullet I shot lost nearly 40% of its weight," said McTee.
"It made me wonder how much of it was left in the field and how much I put in my freezer, or gave to my parents. I feel like a lot of hunters have the same questions."Most lead-core rifle bullets fragment into hundreds of tiny pieces when they strike animal tissue, said National Park Service(NPS) Pinnacles bulletin.
Lead-tainted meat may become part of scavengers' food supplies when any of the following occur: a wounded animal escapes a hunting attempt, an animal shot as a pest is not retrieved from the field, or when gutpiles remain on the landscape after a hunt. Other scavengers that are affected by eating spent lead ammunition include hawks, ravens, turkey vultures, and grizzly bears.
"I switched to copper bullets to minimize meat damage," said J.R. Long, Seeley Lake. "When I shot a deer in the chest and opened it up, it looked like a grenade had gone off inside of it. A decent copper bullet is a little more expensive than lead, but the bullet stays together."
According to a statement from the Raptor View Research Center: "It is our belief, that over time, we will see a decrease in lead levels of our sampled eagles, as people learn more about the health hazards (to humans and wildlife) of using lead based ammunitions for hunting."
Reader Comments(0)