We used radiotelemetry to investigate patterns of space use of the California red-backed vole (Clethrionomys californicus) on a remnant of forest in southwestern Oregon. We radiotracked four voles and mapped the locations of logs of varying decay classes within the home range of each vole. Of the collective locations of voles, 98% coincided with downed logs even though logs covered only 7% of the areas of estimated home ranges. Furthermore, voles used logs in later stages of decay significantly more often than logs in earlier stages of decay. This high use of decayed logs suggests that decayed logs are a critical component of suitable habitat for voles.