Lead Poisoning Study

NEWS RELEASE
For Immediate Release

Contact:
Sue Kirchoff, U of M College of Veterinary Medicine, 612-624-3781

Lead Slugs May Be Cause of Lead Poisoning in Bald Eagles
Deer carcasses and gut piles to be X-rayed

MINNEAPOLIS/ST. PAUL (Nov. 17, 2004) - Suspecting that lead slugs from downed deer are responsible for lead poisoning in bald eagles, The Raptor Center at the University of Minnesota will engage in a study to determine the presence of lead in deer killed with lead slugs. As part of a special weekend hunt on Saturday, Nov. 20, carcasses and gut piles of 12 to 15 deer harvested by shotgun will be evaluated through direct examination and radiography. The special hunt will be held at Elm Creek Park Reserve in Osseo, Minn., from 8 a.m. to 5 p.m.

Hunters participating in the study will complete a questionnaire about the size and kind of slug used, the approximate range and angle of the shot, and the targeted area on the deer at the time the kill shot was fired. Deer carcasses and gut piles will be transported to Anoka Equine Clinic, where they will be X-rayed. After radiography, the tissues surrounding the bullet will be retrieved and saved for validation purposes. Deer will be returned to hunters after the examination is complete. The study is done in partnership with the University of Minnesota Veterinary Diagnostic Laboratory, Minnesota Department of Natural Resources (DNR), Three Rivers Park District, Anoka Equine Clinic, and Minnesota deer hunters.

The Raptor Center has studied lead poisoning in bald eagles since 1975, both by measuring lead residues in plasma and by radiographing birds.

"Back in the 1980s, we thought that lead poisoning in bald eagles was caused by the use of lead shot in waterfowl hunting," said Pat Redig, D.V.M., Ph.D., director of The Raptor Center. "In 1991, federal legislation outlawed the use of lead shot for waterfowl hunting. But that didnt reduce the incidence of lead poisoning in bald eagles. About 25 percent of the bald eagles we treat test positive for lead poisoning."

In the late 1990s, a study funded by the Minnesota DNR found that 60 percent of free-flying eagles trapped at their wintering grounds along the Mississippi River had elevated lead levels in their blood. A connection between high eagle admissions with lead poisoning, deer hunting season, and the presence of irregularly shaped lead fragments and deer hair in the stomachs of sick eagles led Raptor Center staff to new hypothesis: Bald eagles were ingesting lead by feeding on downed deer and gut piles during deer-hunting season.

A 2003 study completed by Michael Fry, Ph.D., at the Department of Animal Science at University of California, Davis, drew similar conclusions about the source of lead poisoning and higher-than-normal lead levels in California condors.

In January 2003, the U.S. Fish and Wildlife Service appointed Redig as chair of the California Condor Lead Exposure Reduction Steering Committee, a subcommittee of the California Condor Recovery Team. The goal of the committee is to work with the hunting community to encourage hunters to change hunting practices to protect California condors from exposure to lead from lead shot. Recommended practices include retrieval of shot animals from the field; hiding carcasses or gut piles by burying them, covering them with brush or rocks, or placing them in an area inaccessible to condors; removing bullets and surrounding impacted flesh when leaving carcasses or gut piles in the field; and use of alternative non-toxic ammunition. The committee will hold its annual meeting at The Raptor Center at the University of Minnesota College of Veterinary Medicine in St. Paul on Nov. 16-17.

The Raptor Center at the University of Minnesota specializes in the medical care, rehabilitation, and conservation of eagles, hawks, owls, and falcons. In addition to treating approximately 800 birds a year, the program provides training in raptor medicine and surgery for veterinarians from around the world, reaches more than 150,000 people each year through public education programs and events, and identifies emerging issues related to raptor health and populations. A program within the University of Minnesota College of Veterinary Medicine, The Raptor Center is supported by private funds.