U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version



Oikos 121: 743–751, 2012; doi: 10.1111/j.1600-0706.2011.19515.x


To determine how black-tailed deer Odocoileus hemionus columbianus respond to phytochemical cues while browsing in heterogeneous phytochemical environments, we offered captive and free-range deer cloned rooted cuttings and seedlings of western red cedar Thuja plicata selected for varying monoterpene content. Black-tailed deer were thus allowed to browse among a controlled array of phytochemical cues in a series of experiments designed to evaluate foraging behavior at fine (within plot) and coarse (plot selection) scales. Within-plot diet selection experiments demonstrated that browse preference for individual western red cedar plants was a function of foliar monoterpene concentration. Individual plant palatability combined with momentary maximization foraging strategy promoted survival of heavily defended plants. Among-plot foraging experiments demonstrated that coarse-scale foraging preferences were strongly influenced by distributions of high monoterpene-containing western red cedar in available plots. Olfaction may play a significant role in both fine and coarse scale browse behaviors of deer as they employ a risk-averse foraging strategy.