Yellowstone bison drive

Montana livestock agents plan a major push over the next week to haze several hundred wild bison back into Yellowstone National Park to protect area cattle ranches from disease. Helicopters, all-terrain vehicles and horseback riders will attempt to drive about 400 animals into the park. The bison had exited Yellowstone over the winter in search of food at lower elevations. Critics say the hazing is unnecessary, particularly in areas where cattle no longer graze. But facing pressure from the ranching industry, Montana officials said they plan to remove all bison from public and private lands around West Yellowstone by May 15. That's about a month before cattle will return to their summer grazing plots. Whether the bison cooperate remains to be seen: Late spring snowstorms have stalled the emergence of grasses inside Yellowstone that bison depend on for forage. The park's chief ranger, Tim Reid, said the delayed "greenup" of Yellowstone could complicate the hazing effort unless warm weather sets in quickly. Reid said if conditions are not right, bison hazed into the park could simply circle around and leave again. The animal disease brucellosis can cause infected animals to abort their young. It has been eradicated nationwide except for the Yellowstone region. About half of Yellowstone's bison test positive for exposure, although the rate of active infections is much lower...more