Located in the middle of Eastern Townships, the eastern chipmunk (Tamias striatus) study site livens up each spring for more than a decade now: a team is working to collect essential data to better understand the importance of genetic and environmental factors on the maintenance of phenotypic variability. Chipmunks are individually marked with ear tags to follow them across time and to collect repeated morphological, physiological and behavioural measurements. Genetic analysis also allowed the determination of their reproductive success and the establishment of their pedigree, thus adding a genetic component to the observed phenotypic diversity. Finally, as chipmunks are sensible to the fluctuation of resources within their environment, the annual variation in the food availability, influenced by mast trees, is also quantified. This huge sampling effort has been rewarded by the quality of the research that it is producing.