JACKSON HOLE, WYO \u2013 A golden eagle was found dead in Yellowstone late last year had levels of lead toxicity that were off the charts, according to biologists.\r\n\r\nThe golden eagle was found dead on December 6, 2018, near Phantom Lake in the northern section of Yellowstone National Park. A recent lab necropsy indicated the cause of death was lead poisoning. Levels found in the golden eagle were extremely high and well above lethal toxicity.\r\n\r\nThe adult female was the first golden eagle in Yellowstone\u2019s history to be marked with a radio transmitter. The marked raptor was part of a study to understand productivity, movements, survival, and cause of death in Yellowstone. The study is being conducted and funded by Yellowstone National Park, University of Montana, Yellowstone Forever, and the US Geological Survey.\r\n\r\nGolden eagles often scavenge during the fall and winter. Scientists suspect the adult female may have eaten carrion containing lead bullet fragments.\u00a0Some advocacy groups have called for hunters to use bullets made of copper to help prevent such deaths.\r\n\r\nEagle scientist Todd Katzner with the US Fish and Wildlife Service called the death "gut wrenching."\r\n\r\nTransmitter data revealed that the eagle ranged extensively during the 2018 autumn hunting season north of the park before it died. Hunter-provided carrion, especially gut piles, is an important food resource for golden eagles and other avian scavengers. The lead levels in the marked eagle indicated it likely ate carrion that contained lead fragments.\r\n\r\nIf carrion contain lead fragments, they can be deadly to scavengers. Lead is an environmental toxin well known for its capability to directly impact wildlife. Studies by Craighead Beringia South, a nonprofit research institute based in Kelly, Wyoming, have shown that fragmented bullets often stay in the discarded remains of wild game and subsequently enter the food chain as they are consumed by other animals. Lead poisoning can result when wildlife species ingest the toxic materials.\r\n\r\nIn November of 2011 and March 2015, Craighead Beringia South researchers from Livingston, Montana, also documented mortalities from elevated lead levels of two golden eagles that ranged north of the park.\r\n\r\nNon-lead ammunition is safer for birds. Read more about non-lead ammunition programs at\u00a0The National Elk Refuge\u00a0and\u00a0Grand Teton National Park.\r\n\r\nGolden eagles are large, long-lived raptors that feed on many medium-sized mammals, birds, and carrion. Yellowstone considers golden eagles a species of concern.