The presence/absence of faunal remains are often used to suggest that shifts in prey choice reflect resource intensification or depression. The archaeological record, however, is typically incomplete owing to issues of discovery, preservation, and data recovery. Though analysis of faunal assemblages provides some indication of diet breadth, they provide little insight as to the relationship between resource potentials and human population densities. We use contemporary/historic harvest data for southern Idaho to assess relative animal population densities, and to calculate potential return rates for deer that are well represented in the archaeological record of the Snake River Plain. In addition, we examine human population densities as the basis for relating possible resource potentials to return rates. The zooarchaeological record of the Snake River Plain indicates that a range of mammalian species were utilized during the Archaic Period (7000-150 BP; Plew, 2009). Optimal foraging models often suggest that shifts in prey choice reflect resource depression associated with environmental changes. The archaeological record, however, is typically incomplete with respect to discovery, preservation, and data recovery. Though faunal assemblages provide some 1