Two new bills introduced in the Montana legislature would usher in a zero-tolerance policy for wild bison, potentially opening the way for a return to the shoot-on-sight practices of years past.Under a proposed bill in the state Senate, Department of Livestock officials would have the leeway to exterminate all wild bison. And a bill in the state House of Representatives would allow landowners to kill any bison that sets foot on private property. The legislation pits farmers angered by the huge bison’s foraging against a consortium of wildlife advocates, Native Americans and hunters who had hoped that rules banning the bison were easing.“Why do