Distribution, range use and population characteristics of mule deer associated with the Schafer Creek winter range, Bridger Mountains, Montana

A study was conducted in the Bridger Mountains of southwestern Montana from June 1976 through April 1978.Objectives were (1) to obtain data on yearlong distribution, range use and population characteristics of mule deer associated with the Schafer Creek winter range and (2) to compare findings with those of earlier studies of deer associated with the nearby Armstrong winter range.Vegetation of the Schafer Creek study area was described as consisting of 5 habitat series, comprising 18 distinct habitat types.Series were: Idaho fescue with 2 habitat types covering 1.7% of the area; big sagebrush with 2 habitat types cov-2.6% of the area; Douglas fir with 7 habitat types covering 61.9% of the area; subalpine fir with 5 habitat types covering 30.7% of the area and; limber pine with 1 habitat type covering 2.9% of the area.Nine adult females and 3 adult males were radio-collared and monitored from the ground and 53 fixed-wing flights.An additional 17 mule deer were neck-banded.Movement from the winter range by marked animals ranged from 0 to 29 km and averaged 4.8 km.Three holding areas were delineated on two major travel corridors which were used by deer arriving on and departing from the winter range.Associations among adult females appeared to affect summer, fall and winter distributions.Home range size of radio-collared deer was: 111 ha for females and 387 ha for males during the mild winter of 1976-77; 178 ha for females and 152 ha for males summer-early fall and; 58 ha for females during the more severe winter of 1977-78.Three radioed deer summering in heavily forested habitats had significantly smaller home ranges than 8 others of broken timber habitats.Deer appeared to habitually use the same winter and summering areas.Douglas fir habitats were the most important in winter, spring and fall, and ranked second to subalpine fir in summer.Douglas fir/ Idaho fescue was the most used habitat type in winter while subalpine fir/virgin's bower appeared to be the most important summer type.Closed canopy habitats were important during spring and fall migrations.Females with fawns occurred with greater than expected frequencies in certain habitat types (PIFL/JUCO and PSME/FEID) during summer-early fall but not during the 1977-78 winter.Forbs and browse were the most important summer forage classes used while browse, grass and forbs, respectively, were the most important winter forage classes.There was an apparent 10-20% increase in population and an increase in fawn production from the 1976-77 winter to 1977-78.Winter mortality was approximately 17-19% in 1976-77, consisting primarily of fawns, and was estimated at a minimum of 15%, including 34% of all fawns in 1977-78.Noted differences between the Schafer and Armstrong areas were: more Douglas fir and subalpine fir habitats with shrub understories on the Schafer summer area; no bitterbrush and much more Douglas fir/snowberry habitats on the Schafer Creek winter range and; smaller home ranges and generally higher winter survival on the Schafer Creek winter range.