By MATTHEW BROWN
BILLINGS, Mont. (AP) -- Yellowstone National Park administrators plan to capture and ship to slaughter potentially hundreds of wild bison if they migrate into Montana this winter in a bid to reduce disease and control the population of the animals.
The captures could begin as soon as mid-February, park officials said.
The effort comes as neighboring Montana is proposing to let bison roam more freely in the 70,000-acre Gardiner Basin north of the park despite resistance from local officials and some cattle ranchers.
Although the moves by the state and park appear contradictory, officials say keeping bison numbers under control is key to increasing public tolerance for the animals.
A mild winter so far has slowed the bison migration. That could scuttle the slaughter plans if conditions persist.
But about 570 bison are close enough to Yellowstone's northern boundary that a significant winter storm could trigger them to move toward the Montana line, park and state officials said.
"We would still estimate 300 to 500 animals to be at the north boundary before the end of winter," said Yellowstone bison biologist Rick Wallen.
The slaughter would target female animals that test positive for exposure to the livestock disease brucellosis. About 50 bison would be diverted to an animal contraception research program.
The park's goal is to remove up to 330 bison from the population this winter to work toward a long-term objective of about 3,000 of the animals. The most recent population count tallied 3,720 bison
Bison advocates criticized the slaughter plan when it was unveiled late last year. They want bison -- North America's largest animals -- to have unfettered access to their historic winter grazing grounds at lower elevations in Montana.
The slaughter proposal also met with a tepid reception from Montana Gov. Brian Schweitzer. The Democrat has been sparring with the park's parent agency, the Department of Interior, over a wide range of wildlife management issues and in December issued an executive order prohibiting any wildlife shipments by Interior without prior state approval.
A similar order last winter blocked bison slaughter shipments just days before they were slated to begin.
Yellowstone Superintendent Dan Wenk said he hoped to develop a cooperative process that will let the shipments proceed if the migration occurs.
"My understanding is that with appropriate notice and appropriate protocols in place, we will be allowed to ship bison to slaughter," he said.
Meat from slaughtered bison would be distributed to American Indian tribes. Many tribes have a strong cultural attachment to the animals and relied on them historically as a primary source of protein.
Park and state officials said hunting in parts of Montana bordering the park remains the preferred method of bison population control. But this year's harvest has been low: state and tribal hunters had killed only 17 bison through Thursday.
The state-sponsored hunt is scheduled to end Feb. 15. Hunts by the Nez Perce, Confederated Salish and Kootenai and other tribes could continue after that date.
But the expectations are low compared to last year, when a tough winter prompted an estimated 1,400 bison to exit Yellowstone and state and tribal hunters killed more than 200.
Copyright 2012 The Associated Press.