Hunting guide Mike Clark normally has more than 20 clients lined up each fall for trips deep into Wyoming's western wilderness to shoot mule deer, prized by hunters for their size and impressive antlers.But unusually cold weather and heavy snowfall that blanketed much of the Western U.S. last winter killed off many young deer. And that prompted wildlife officials throughout the Rocky Mountain states to take measures such as reducing the number of hunting permits to try to help devastated wildlife populations rebound.Clark took only six mule deer hunters out in September and October who were lucky enough to get permits. He estimated that he lost 40 percent of his income as a result. If it wasn't for the hunters he was guiding this year to shoot elk that generally survived the brutal winter, Clark said, 'We'd pretty much be selling out.'In one remote part of Wyoming's backcountry where peaks soar to 11,000 feet (3,300 meters), state wildlife managers documented the loss of all fawns they had been monitoring in a mule deer herd.To help the herd recover, the Wyoming Game and Fish Commission reduced the number of deer permits for out-of-state residents from 600 to 400 in the area where Clark operates, cut the hunting season to 22 days and limited hunters to killing older bucks.Officials won't know how effective their efforts will be until hunting season ends in January and hunters submit reports saying how many deer they killed.Colorado, Idaho, Oregon, Utah and Washington state also imposed hunting limits to help isolated wildlife herds recover from the winter. Deer were hit hardest in most of those states, while Washington had severe losses among several of its elk herds.In southern and central Idaho, last winter's fawn survival rate was just 30 percent, prompting a reduction in deer hunting permits to help herds boost their numbers, said Mike Keckler, spokesman for the Idaho Fish and Game Department.'We're trying to bring them back up,' he said.And in Washington, the number of elk hunting permits was cut drastically in some parts of the state where elk died in droves, said Brock Hoenes, statewide elk specialist with the Washington Department of Fish and Wildlife.The area of Wyoming where Clark takes hunters is known as one of the best places in the world to hunt mule deer, state Game and Fish spokesman Renny MacKay said. He added that the decision to limit permits was difficult for state officials to make.Clark said his business will survive the downturn but that his future guiding hunters is uncertain if wildlife managers reduce the number of mule deer hunting permits for nonresidents again next year.'Otherwise, none of us are going to have any deer hunters,' he said.