CHEYENNE - Spokesmen for the Wyoming Game and Fish Department and the Rocky Mountain Elk Foundation say they don't oppose a request from federal land managers in the northwestern part of the state that elk and bison hunters volunteer to use non-lead ammunition.

Managers at Grand Teton National Park and the National Elk Refuge say lead is an environmental toxin that can poison birds and other animals that eat carcasses shot with bullets that contain it.

Steve Kallin, elk refuge manager, said Friday that a recent study shows a compelling link between elevated blood levels in ravens and eagles and the start and end of hunting season on the refuge.

"These data have not shown any population level impacts, but it has shown that there are some individual birds that may be suffering ill effects," Kallin said.

Thousands of elk hunters will pursue their prey on the national park and on the refuge this fall, Kallin said. He said between 300 to 400 hunters will also go after bison on the elk refuge.

The federal government already requires the use of steel shot for hunting ducks and other migratory birds to reduce lead exposure. The National Park Service announced this spring that it intends to eliminate the use of all ammunition containing lead and lead fishing tackle in parks by the end of next year.

However, Kallin said he has seen no indication that the U.S. Fish and Wildlife Service, which manages the elk refuge, intends to push for any ban on the use of bullets that contain lead.

"This is a localized program," Kallin said. "I'm unaware of any other national wildlife refuge that's going to this voluntary program for big game hunters."

Kallin said he's personally used non-lead ammunition for hunting and has been satisfied with its performance. He said non-lead bullets, typically made out of copper alloy, are only slightly more expensive than premium bullets that contain lead.

"In the context of an entire elk hunt, it's a relatively minor increase in cost," Kallin said.

The state of California last year started banning bullets containing lead in the 15 counties where endangered condors live. Arizona has a voluntary effort in which wildlife officials give hunters non-lead bullets to reduce lead poisoning of condors from animal carcasses.

The National Shooting Sports Foundation, a firearms industry group, has protested state bans on bullets containing lead. The group says it sees a lack of scientific information that would justify such bans.

Eric Keszler, spokesman for the Wyoming Department of Game and Fish, said Friday that the state game commission has been monitoring the non-lead bullet issue.

"I guess we wouldn't support or oppose it," Keszler said of the federal agencies' suggestion that hunters use non-lead bullets. "That's one of the issues that our commission has been looking at pretty intensely over the last couple of years."

Dan Crockett, director of publications for the Rocky Mountain Elk Foundation in Missoula, Mont., said Friday that his group has been following the non-lead ammunition issue, particularly in the Arizona condor country.

"I think the way the refuge is going at it and leaving it up to the hunters discretion is probably a sensible way," Crockett said. He said there's ample evidence, both anecdotal and scientific, that hunters can kill elk with either type of bullets.