I evaluated the use of sign indices as indicators of relative vole population abundances in grasslands and agricultural systems in western Oregon grasslands. The development of a reliable index based on vole sign that does not rely on the repeated use of traps would greatly aid rapid assessment of relative population densities, and allow greater flexibility in both research and management. I tested the presence and number of burrows, runways, droppings, and damaged vegetation along transects and in quadrats to evaluate each metric's correlation to estimated population size. Vole population size was estimated with mark-recapture techniques. None of the indices performed well, particularly in situations where plots were mowed. The number of animals captured on the first trapping occasion was most correlated with estimated population size. Indices for vole abundance should be tested in the system and with the species of interest prior to their use in research or management.