JACKSON, Wyo. — In the three decades since 18 bison stumbled onto a federal elk feeding ground outside this mountain town, the herd has ballooned to 1,200 animals — one of the largest groups of bison in the United States.

But the National Elk Refuge was not created for bison, 6-foot-tall, 1-ton brutes also known as buffalo. Since their arrival, the bison have pushed elk off the refuge's artificial feed lines, trampled its 25,000 acres of grasslands and introduced diseases that put livestock at risk.

Beginning Saturday, refuge officials and state wildlife officials will hold annual hunts aimed at cutting down the herd by at least 700 animals over the next few years. Hunters are entitled to one bison each.

Meanwhile, the artificial feeding will continue each winter, angering animal rights groups and environmentalists who say the government is baiting bison to unnecessary slaughter.

Refuge managers agreed that feeding the very bison they want hunters to shoot was not ideal. They said the conservative politics of northwest Wyoming — home to Vice President Dick Cheney and a strong hunting culture that is a driving economic force — gave them little choice.

"It's a political compromise," said Eric Cole, the refuge's wildlife biologist. "The worst-case scenario is the hunt doesn't happen and we have 1,200 bison. That's a lot of mouths for a limited land base."

Through a separate hunt, federal and state officials want to reduce the refuge's elk population, from almost 8,000 animals to about 5,000.

Yet it's the plan to kill bison that has garnered the most objection. That's because of the animals' docile nature — hunting them has been compared to hunting a sofa — and their iconic status as a last vestige of the once-wild American West.

"It's senseless and it's inhumane," said Jonathan Lovvorn, an attorney with the Fund for Animals.

The group filed a lawsuit in 1998 seeking to stop the hunt, which forced the federal government to delay the killing of bison until an environmental study was completed earlier this year.

Refuge manager Steve Kallin said the bison hunt would have been much smaller if the Fund for Animals had never filed a lawsuit. When a hunt was first proposed in 1998, there were about 500 bison on the refuge — a number Kallin said could have been sustained by hunting 70 animals a year.

Most states forbid or discourage feed grounds because they allow the easy transmission of wildlife and livestock diseases. Aside from the elk refuge, there are 22 state-run feed grounds in northwest Wyoming, a region of towering mountains and fertile valleys where punishing winters routinely kill off wildlife.