HELENA — A federal judge on Monday blocked Montana officials from driving wild bison back into Yellowstone National Park with a helicopter after wildlife advocates argued hazing from the air could harm grizzly bears in the area.
The ruling by U.S. District Judge Charles Lovell grounds plans by the Montana Department of Livestock to hire a helicopter Tuesday to haze about 70 bison out of the Hebgen Basin west of the park before cattle are moved into the area to graze.
Christian Mackay, the agency's executive officer, said he will instead ask the state wildlife department and National Park Service for additional personnel to assist six or eight horseback riders now slated to drive the bison on the ground. He said he did not know how effective they will be without the noise from the air to scare the animals.
"We're about to find out," Mackay said. "We're going to put forth every effort to return them to the park."
Hazing is an annual event to drive back bison that had wandered from the park in search of food at lower elevations during the winter. The helicopter flights are authorized and paid for by the state Department of Livestock in coordination with state and federal agencies that oversee the Interagency Bison Management Plan that governs bison movements around Yellowstone.
Lovell granted the temporary restraining order after a hearing in Helena in which attorneys for the wildlife advocacy group Alliance for the Wild Rockies argued state and federal officials had not properly studied how the use of helicopters affects grizzly bears.
Grizzlies are threatened under the federal Endangered Species Act, and the advocacy group says the hazing flights can drive bears from their habitat around the Yellowstone ecosystem.
"The helicopter can't distinguish between a bison and a grizzly bear," alliance attorney Rebecca Smith said. "These areas are the last habitat refuges for grizzly bears."
Smith said there is scant analysis on the effects of helicopters on grizzlies contained in the Interagency Bison Management Plan that is used as the authority for hazing operations. The bison management plan assumes grizzlies will still be in their dens when the hazing occurs, when in reality bears are very active in May, June and July.
The advocacy group wants the agencies involved in the Interagency Bison Management Plan to conduct a new scientific study on the effects on grizzlies.
Department of Justice attorney Coby Howell argued a bear fleeing a short distance after being startled once by a helicopter is a temporary displacement that does not threaten the entire species.
The bison management plan already accounts for grizzlies by ordering a hazing operation to stop when there is one in the path, he said.
"We don't deny there are grizzly bears in the area. If actual operations run into a grizzly bear, then they cease," Howell said.
The livestock agency twice last week used a helicopter to haze bison back to the park, but 70 of those bison have returned to the Horse Butte Peninsula west of Yellowstone, Mackay said.
Smith said the Department of Livestock doesn't actually know the location of grizzlies outside the park because it does not coordinate with the U.S. Forest Service. A Forest Service employee spotted a grizzly a half-mile away before hazing operations began last Wednesday, and the operation was not halted.
The Alliance for the Wild Rockies last year had asked Lovell to block the helicopters, but Lovell ruled against them after determining the state agency had completed its hazing operations and concluding there were technical problems with the advocacy group's request.
Lovell, in granting the temporary restraining order, did not say why he was ruling in favor of the wildlife advocates. But the lawsuit the group filed last year challenging the use of helicopters is still pending, and Lovell said during Monday's hearing that he was surprised that the Department of Livestock would order additional helicopter hazing before that case had been resolved.
Lovell also said that the problems he found with the group's previous request last year had been fixed, and he questioned what state and federal agencies had done to specifically address bears at the site of a hazing operation when their population already has been diminished.
"Great care should be taken to make sure they're not taken or distressed in noncompliance of the law," Lovell said.