Hiking the heads of coulees and glassing from a vantage point helps locate the deer. Remember, bucks are running most of the day, fueled with the lust of the rut. When you spot a buck you want, move toward him by following coulees and washes. At the onset of winter, mule deer in the mountains of central and western Montana stream out of the high country and head to the foothills. Often an inversion sets in, with cold, stagnant air trapped in the valleys by a blanket of warmer air circulating above. By climbing above the inversion line, mule deer are rewarded with temperatures 20 degrees or so warmer than below. You can see these inversion lines where a ceiling of fog and clouds of stagnant valley air meet the clear, warmer air circulating above. Glass along this line at the edges to spot a buck tending his harem of does. You're most likely to sight a shooter early and late in the day.