A Yellowstone National Park biologist says she'll recommend that portions of the park be closed during winter to make it harder for bison to migrate outside park boundaries.

But a park spokeswoman said Wednesday that Yellowstone "has no intention of closing the park to winter use."Biologist Mary Meagher spoke Tuesday night at the Museum of the Rockies in Bozeman, and talked about the long-range bison management plan under development.

One of the plan's options is closing the park during the winter, Meagher said. The bison use plowed roads, bridges and snowmobile trails to expand their range, she said. Skiers, snowmobilers and snow-coach riders are among those who use the park during the winter.

Montana officials want the bison to stay in the park because some of the animals are infected with brucellosis, a disease that causes domestic cattle to abort their calves. Under a short-term management plan now in effect, hunters, game wardens or park rangers may shoot bison that migrate from the park into Montana during the winter.

Montana's bison "hunt," carried out since 1985, has spurred a nationwide controversy over whether the animals should be shot once they leave the park.

The bison traditionally seek lower areas during the winter, in search of forage.