MISSOULA — A conservation group has bought 71 acres in the Yaak Mountains in northwestern Montana near Troy that officials say could improve migration corridors for grizzly bears and other wildlife in the region. The Missoula-based Vital Ground Foundation bought the land this week from a private landowner. The parcel is located in the 2,600-square-mile Cabinet-Yaak Grizzly Bear Recovery Zone that also includes northern Idaho. Foundation spokesman Ryan Lutey tells the Missoulian that the purchase was its top priority because of adjacent U.S. Forest Service land. Lutey says the land offers low-elevation habitat for wildlife along the Kootenai River and is ideal winter range for deer, elk and moose. Lutey says the corridor will help sustain the viability of endangered grizzly bear populations in the U.S.