Voles are little rodents that burrow underground as well as form tunnels in the grass above ground.
For this particular home owner, their home was on a raised adobe clay property. Three of the sides of the hill this home was on, was covered in very long grass. The perfect place for Voles to thrive.
For Vole Extermination, we did a combination of gassing the tunnels and set several traps in the runway paths above ground. We killed several in these traps using this strategy. Unfortunately, we also trapped a Gopher Snake in the same pair of traps (likely chasing the Vole), in one of our runway traps.
Snakes are a great creature to have in your yard as they help maintain the population of any rodents in the area as in this case, Voles. As a side note, Hawks, Kestrels and Owls are also great birds of prey to have in your area.