We examined the assertion that seasonal fluctuations in food availability are necessary for vole cycles to take place by studying the dynamics of a California vole (Microtus californicus) population inhabiting a relatively aseasonal environment. That population was one of the most stable (noncyclic) microtine populations yet described. Reproduction was comparatively aseasonal but appeared to be suppressed at high population density. We suggest that the role of seasonality in vole population fluctuations deserves further study.
Cranial morphology of the California vole (Microtus californicus, Cricetidae) in a contact zone
