Mattfeld, George F. 1974. The Energetics of winter foraging by white-tailed deer: A perspective on winter concentration. Ph.D. Dissertation, State University of New York, College of Environmental Science and Forestry, Syracuse, 306 pp.
Abstract: Winter concentration behavior of the white-tailed deer (Odocoileus virginianus) was reviewed with respect to its anatomical and physiological adaptations for survival in severe climates. Energy expenditure in relation to forage energy available was shown to be dependent on snow accumulation and differences in the distribution of forage species. Classical respiratory collection techniques were employed to estimate the energy expenditure of locomotion and travel in snow with five deer. Logarithmic increases in energy expenditure occurred when the deer sink more than 25-40 cm into the snow pack. The expense of travel in snow was affected by the nature of the snow pack and estimates were improved empirically with measurements of the snow's resistance to dynamic loading. Coniferous forest types used by deer were shown to have significantly less snow accumulation and contagiously distributed, digestible forage, in contrast to the poorly digested and uniformly distributed forage found in sampled hardwood stands. Deer trails in concentration areas were associated with clumps of forage and coniferous crowns, suggesting a more efficient collection of forage energy than would be possible in hardwood types. Net energy availability was shown to be a mechanism with great potential to produce the pattern of behavior characterized as "yarding." In some winters survival in hardwood stands appeared to be impossible. Survival of deer in the northern portions of their range, and reasonable management of the resource, appeared to be dependent on year round nutrition and snow accumulation as it affects net energy availability.