Based upon the literature on North American deer, a nutritional model was developed for mule deer (Odocoileus hemionus) which examines deer requirements for protein, energy, and phosphorus. Vegetation biomass, vegetation nutrient content, and mule deer diets, as indicated by fecal analysis, were measured on two deer ranges (Duck Creek Basin and Badger Mountain) in Nevada. The calculated requirements were compared to the ability of the habitat to supply these nutrients, and surplus nutrients obtained by deer were assumed to be utilized for fawn production. Fawn production calculated could then be compared to observed fawn production to determine the adequacy of the model. Results indicate that the model developed is inadequate in several respects, but may be suitable for determining limiting habitat factors and relative habitat quality. Duck Creek deer produced 97 fawns per 100 does in 1978, while model results predicted that only 50 fawns per 100 does could be produced. On Badger Mountain, observed fawn production was 57ff:100 dd, while predicted fawn production was 10ff:100 dd. The resulting underestimation of habitat quality was thus 55% and 84% for Duck Creek and Badger Mountain, respectively. Although the model underestimates habitat quality, it may be useful in predicting habitat factors which limit deer herd productivity. Duck Creek deer productivity was found to be limited by availability of energy, and Badger Mountain productivity was probably limited by phosphorus availability. Inadequacies of the model are discussed.
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