If those wolves are eating elk, go out there and make elk sounds. In Alaska, I have heard of more than one hunter calling in wolves, while moose calling. (And grizzlies) My brother-in-law got a triple on wolves that way, two years ago. That boy can shoot! He was antler rattling, and doing moose vocals, and called 'em right in. Of course howling can be effective, too. Also, watch for scavengers, such as magpies, ravens, and eagles that might indicate a wolf kill nearby. Snow would be good.