BILLINGS, Mont. — Yellowstone's grizzlies are going to be particularly hungry this fall, and that means more dangerous meetings with humans in a year that is already the area's deadliest on record. Scientists report that a favorite food of many bears, nuts from whitebark pine cones, is scarce. So as grizzlies look to put on some major pounds in preparation for the long winter ahead, scientists say, they will be looking for another source of protein – meat – and running into trouble along the way. Wildlife managers already report bears coming down off the mountains and into areas frequented by hunters, berry pickers and hikers. "Pack your bear spray: there's going to be run-ins," said grizzly researcher Chuck Schwartz with the U.S.