Study Reveals Lead Poisoning in Most U.S. Eagles


| LAST UPDATE 02/20/2022

By Stanley Wickens
u.s. eagle lead poisoning
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It hasn't been long since the national bird of the United States was removed from the government's list of endangered species. But unfortunately, findings from a recent study might indicate that they're still at a growing risk of extinction.

As it turns out, hunting season isn't just deadly for elk or deer, but also for the bald eagles and golden eagles that then scavenge the prey's remains. According to a study recently published in the journal Science, eagles are consuming lead particles from bullets found in the carcasses of animals shot by hunters. "Every single time a lead bullet hits a deer, it fragments into many, many pieces," Todd Katzner, co-author of the study, and a wildlife biologist at the U.S. Geological Survey told Insider. "It only takes a tiny fragment, something the size of the head of a pin, to kill an eagle." After examining the blood, bone, liver, and feathers of over 1,200 eagles in 38 U.S. states, researchers detected high levels of chronic lead poisoning among the two types of eagles.

u.s. eagle scavenging lead
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Study co-author Vincent Slabe, a wildlife biologist at Conservation Science Global, explained that these levels of lead poisoning are slowing the population growth rate of the two species. While acute lead poisoning can cause the birds to become immobile and starve to death, chronic lead poisoning can have more covert effects. Some of these effects include weakened abilities to move and fly, decreased sperm quality, a hindered ability to swallow and digest food, and lowered immunity. Unfortunately, any amount of lead consumption can lead to these horrible consequences.

For decades, conservationists have been calling for regulations to force hunters to use steel or copper ammunition instead of lead. "It is really frustrating that lead poisoning in birds of prey has been well known for more than 50 years, and there have been very limited movements in the regulations adopted in most of the countries," says Rafael Mateo Soria, a researcher at Spain's Institute for Game and Wildlife Research. Sadly, scavenging birds in Eurasia face the same fatal conditions in the wild. But with the help of ongoing research and advocacy, we'll continue to hope for a better future for these fascinating creatures who play a vital role in our ecosystem.

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