Feeding Deer on Browse Species during Winter

Abstract

T HE encroachment of civilization has resulted in restriction of deer ranges throughout the west. Nowhere is this more serious than in Utah. The problem presented by the scarcity of deer range has many facets. Among these, the food habits of mule deer and knowledge of the value of plants used by them in winter are of great importance. The investigation reported herein was undertaken to supply information upon these subjects, and is part of cooperative study involving the U. S. Forest Service, the Fish and Wildlife Service, and the Utah State Fish and Game Commission. Funds were made available for the study by the latter agency. During the winter months of 1948, two mature deer were held captive near Logan, Utah and fed native browse plants. The deer were nearly two years old. The feeding period began on January 2 and closed March 9, 1948. A total of 17 species of forage plants were included in the diet. These included all the plants common on deer winter range which were available near Logan. Big sagebrush (Artemisia tridentata typica), Utah juniper (Juniperus utahensis), and Rocky MIountain red juniper (J. scopulorum) were, except for the first few days, kept before the animals at all times. Two additional plants were offered each day in such sequence that all possible combinations of plants were included except that the hybrid mountain mahogany and black sage (Artemisia tridentata nova) were not so rotated. The first is uncommon, the second infrequently present on deer winter ranges. All the material offered was weighed before being placed before the deer and reweighed as it was removed. Bundles of forage unavailable to the deer were exposed in a manner similar to those fed to the deer to provide a correction factor where changes of weight occurred from causes other than eating by the deer. Such weight changes were insignificant except when storms occurred. Periodically samples of vegetation were dried to provide a basis for converting all figures to air dry weights.