Native hunters of the Northwest Coast valued the local wapiti subspecies (Cervus elaphus roosevelti) greater than any other land animals as a source of both food and raw materials for tools. Wapiti population size depends on the quantity and quality of their preferred foods: easily digestible, high protein plants that occur most abundantly in meadows and thickets, particularly after spring and summer rains. Changing climate regimes affected the productivity of these foods but there is disagreement about whether climate periods with long dry summers helped or hindered wapiti populations on the Northwest Coast. Lepofsky et al. (2005) suggests wapiti abundance increased in periods with persistent summer drought due to increased fire frequency destroying forests and expanding meadows, and increasing the productivity of their preferred foods. While Broughton et al. (2008) suggests wapiti abundance decreased in periods with low spring-summer precipitation due to reductions in the duration and forage quality of the growing season. The goal of this thesis is to eliminate one of these hypotheses with a systematic analysis of wapiti remains from six sites in western Whatcom County representing 300 to 5300 cal yr BP. Stable isotope analysis of nitrogen and carbon in wapiti bone collagen from contexts closely associated with radiocarbon dates. Mammal remains from levels closely associated to these radiocarbon dates were separated and counted to determine mammal NISP, and wapiti remains were identified to determine wapiti NISP. The relative abundance of wapiti was determined by dividing wapiti NISP by mammal NISP and converting to a percentage for each radiocarbon date, and for each climate period. Relative wapiti abundance was found to be dependent on climate period, with significantly lower wapiti abundance relative to other mammals during hot, dry climate periods. The δ13C values are low compared to other regions worldwide and remain stable through time suggesting that closed canopied temperate rainforests were the dominant terrestrial environment over the last 5300 calendar years. During the Medieval Warm period δ15N values are significantly higher suggesting that the hottest driest conditions of the late Holocene occurred at that time. During the warm dry climate periods such as the Medieval Warm Period, increased seasonality would lead to reduced hunting return and plant forage rates for people.