Tractable deer were used to determine food preferences of mule deer on the winter range of the North Kings deer herd from December 1974 through April 1975. The site used for winter range food preference sampling was located in Haslett Basin, Sierra National Forest. During the study, 33,268 bites were recorded in 10,286 minutes of observation. In the feeding trials, 122 food items, including 117 species of vascular plants were utilized by the tractable deer. Food preferences of the deer varied considerably throughout the season. Browse was the dominant forage choice of the tractable deer in early winter, decreasing in use as grasses and forbs became abundant in late winter. Browse again became the most important component of the diet in late spring when its new growth emerged. Oaks (Quercus Wislizennii and Q. Douglasii) and Mariposa manzanita (Arctostaphylos mariposa) were the most important browse species used by tractable deer. Rusty popcorn flower (Plagiobothrys nothofulvus) and filarees (Erodium spp.) were the most important forbs in the tractable deer diet while annual bromes (Bromus spp.), creeping spike rush (Helocharis palustris) and sedge (Carex breviligulata) were important grasses and sedges used for food. No significant difference in forage choices between morning and evening sample periods or between sexes was found. Selectivity indices were calculated for important species in the diet. About 75 percent of the important plant species were eaten in proportion greater than their relative abundance. The use of tractable deer appears feasible as a field technique if investigators desire to determine exactly what foods are used or acceptable to deer.
|
