FEEDING-HABITS OF MULE DEER ON FALL, WINTER, AND SPRING RANGES NEAR KAMLOOPS, BRITISH-COLUMBIA

Diets of mule deer were studied in the Kamloops area [Canada] from Sept. to April. The forages of 67 rumen samples were sorted to grass, tree, shrub and forb species and the percent oven-dry weights calculated for each. Polynomial regressions (to the 3rd degree) were used to describe the use of each plant-growth form over time, as well as to determine the influence of snow depth on plant species consumption. Douglas fir formed most of the tree component of the diet of the deer. Consumption of this species was highest in Dec. and Jan. Grass consumption was less than 10% until early spring when it increased to almost 100%. More forbs were consumed in fall than in winter, while shrubs were consumed more in early fall and late winter than in late fall. Species composition of each plant growth-form generally varied with season. Increasing snow depth altered the proportion of both small and large plants in the diet. As snow depth increased, fewer small plants but more large plants were consumed.