Every now and then, a hiker, climber or biologist lays eyes on a mountain goat in the nooks and crannies of the mighty Teton Range. There’s a good likelihood that the unwanted, nonnative animal doesn’t survive long after the authorities pinpoint its presence. That’s because the National Park Service is now removing all mountain goats that survived an intensive three-year effort to rid the Tetons of the species. A striking white alpine species, mountain goats are being targeted by gunners