Nov. 11, 2014: The 9th Circuit Court ruled that it was okay to "haze" wild bison with helicopters in the springtime to encourage the bison to return to Yellowstone National Park.
Each winter, Yellowstone's bison migrate to lower elevations for better grazing. Often this migration includes crossing the park's north boundary into Montana towns and cattle country. Previous rulings have protected the bison in the winter, even if they are on private property. But, in the springtime, the Montana Department of Livestock has been using cowboys on horseback, off-road vehicles, and even helicopters to coax the bison back to the national park.
The Alliance for the Wild Rockies has been observing this "herding" process and has expressed concern that the helicopters will disrupt grizzly bear activity. Grizzlies are endangered and therefore are protected from harassment. The Alliance first sued the Montana Department of Livestock and other agencies in Montana court. While waiting for judgement from Montana, the National Park Service consulted with U.S. Fish and Wildlife and could find no evidence that the grizzlies were being harmed. The Missoula court case was dismissed and a unanimous appellate panel of the 9th Circuit agreed with the stipulation that if grizzly were in the area, the helicopter herding would stop.
Full article: http://www.courthousenews.com/2014/11/20/bison-herding-copters-dont-bug-bears-9th-says.htm