Yellowstone might be at its big-game best in September. Bull elk are bugling and rounding up their harems. Fleet-footed pronghorn bucks are chasing does as they ward off other suitors with the same intentions. The bison mating season is over, leading to a wildlife spectacle of another sort. Bulls wounded or malnourished from the rigors of the rut are dying in the park and their carcasses quickly attract grizzly bears and wolf packs that quickly attract a crowd of roadside viewers. September has been discovered by wildlife enthusiasts around the world.