An innovative use of white-tailed deer (Odocoileus virginianus) foraging behaviour in impact studies

Abstract

We developed an innovative method for estimating human impacts on animal species by measuring changes in feeding behaviour. We illustrate our approach with a study of the effect of vegetation control in a power-line right-of-way (ROW) passing through essential winter habitat of white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)) at the northern limit of their range. We used giving-up densitiy (GUD; i.e., the amount of food left behind when an animal stops foraging in a patch) to evaluate, in one deer yard, if the loss of forest shelter caused by the power-line installation had a greater effect on deer than the gain of food regenerated in the cleared area. We used GUDs to compare deer estimate of habitat quality in the ROW and in the forest. Our results suggest that the ROW had a negative impact on deer. GUDs were lower in the forest compared with the ROW. Either increased metabolic costs or increased predation risk in the ROW, apparently the latter, lead deer to abandon more food in the ROW than elsewhere. Higher GUDs were strongly correlated with greater snow depth in the ROW. Deer preferred habitats at the edge of the ROW where food and cover were both available.