HELENA, Mont. (AP) — The annual hazing of bison into Yellowstone National Park is underway, prompting a wildlife organization’s latest attempt to block the use of a helicopter to drive back the animals that crossed the park’s boundary over the winter.

The Alliance for the Wild Rockies filed its request for an emergency injunction Monday with the 9th U.S. Circuit Court of Appeals, saying low-altitude helicopter hazing harasses and displaces federally protected grizzly bears in the area.