Less than a week after 25 wild buffalo from the nation’s last purebred herd were permitted to roam into Montana, officials have shot and killed one bison and were debating the fate of 14 others.

Government wildlife managers on January 19 drove a trial band of buffalo, or bison, from Yellowstone National Park into nearby Gallatin National Forest in Montana to use winter grazing grounds for the first time in more than a century.

The plan represented a hard-won agreement among federal and state governments, ranchers and conservation groups over an animal that symbolizes the American West.