Suspended 35 feet in the air from tripods made of tree trunks, two members of the group Buffalo Nations keep vigil.


They are here to prevent the Montana Department of Livestock from building a bison pen outside West Yellowstone, Mont., near Horse Butte, about 15 miles from Yellowstone National Park. The department wants to capture errant bison and test them for the disease brucellosis (HCN, 12/22/97). Protesters spend 24-hour shifts suspended from the tripods, which block the road to the capture site.


"If they have a capture pen on Horse Butte, then they will kill more buffalo," says activist Sarah Chalmers. "We don't want it to be easy to come in here and put up this trap."


Montana officials have killed 15 bison this winter. Six others tested negative for brucellosis and were returned to the park.


The state Department of Livestock says that the bison migrating out of the park endanger Montana's cattle industry. Critics disagree. For two years, the federal Animal Plant Health Inspection Agency has said that the state can allow bulls, calves and yearlings to wander outside the park in some places without threatening the state's brucellosis-free status.


In January, Montana officials announced they would not adopt APHIS's "low risk" policy. "We are here to protect Montana's livestock industry," said state veterinarian Arnold Gertonson. "Any bison that tests positive for brucellosis is a potential threat and will be sent to slaughter."


Park Service officials, meanwhile, are trying to keep bison inside Yellowstone. On Jan. 29, they hazed 13 bison near Gardner, Mont., further into the interior of the park.


- Rachel Odell