So far this year dry conditions and the lack of snow have led Idaho Department of Fish and Game to change its aerial survey plans because big game are spread widely rather than confined to typical winter range.
Aerial surveys are conducted mostly during winter months when the animals are congregated on lower elevation winter ranges. The winter months usually bring three elements needed to conduct accurate surveys: clear weather for good visibility; animals are confined to a smaller geographic area; and snow covering to aid in locating and identifying species. A helicopter flying low and slow is often the most efficient tool for gathering big game herd information.
Fish and Game has conducted more ground surveys for mule deer than is typical because of the lack of snow. Ground counts, along with other information typically used such as harvest data, habitat conditions, and winter survival estimates are part of the process Fish and Game uses to propose big game hunting seasons.
See what biologists see at http://www.youtube.com/watch?v=ShHdGO9j1tg.