Phenologies represent the annual timing of life cycle events, and are the ecological traits most affected by climate change. Hibernation phenologies, however, have received considerably less attention than analogous traits (e.g., migration). As a result, we have a relatively limited understanding of natural causes of variation and, therefore, equally limited ability to forecast how wild populations of hibernators will respond to climate change. We have shown in a wild population of Columbian ground squirrels (Urocitellus columbianus) that natural variation in hibernation emergence date is both heritable and phenotypically plastic. We have also learned that population growth rates are lower in years of later average emergence. In total, these results suggest that emergence date is a fitness relevant trait and is likely to respond to climate change. However, the pace and magnitude of a future responses will depend fundamentally on the relative roles of phenotypic plasticity and microevolution. To further explore the capacity for these two processes in Columbian ground squirrels, we completed a reciprocal translocation experiment. Individuals were relocated across two populations varying in elevation (and consequently, emergence date) in the Rocky Mountains of Alberta, Canada. Our results confirm that Columbian ground squirrels display considerable phenotypic plasticity, but responses across the two translocations were asymmetric (individuals relocated from low to high elevation responded more effectively than those in the reverse). Responses to future climate change in this wild hibernator may thus be complex and spatially variable.