Hole' Vole'-maybe not
Having purchased about 60 hostas the last two years, and only recently become aware of potential vole damage (through this forum), this past year I was on the lookout for vole activity. I found several areas that I assumed were vole holes and set mouse traps baited with peanut butter. The traps were set under a plastic flower pot with a door cut out so the vole in order to exit the vicinity of the hole had to pass over the trap. Whap! I immediately caught three critters which I assumed were voles but after a closer look they turned out to be Northern (Big) Short-tailed Shrews.
I thought this was atypical and figured the shrews, since they were caught out of one hole, had taken over a vole hole and nested. I didn't think the shrews being primarily carnivores would be attracted to peanut butter so I reset the traps in three more locations without the flower pot cover to guide them. Whap! Three more shrews. Not good. I assume the shrews to be beneficial by eating slugs, snails and perhaps even voles.
I thought about using d-CONN mouse poison but figured if the shrews were attracted to peanut butter they might also eat the poison. I then tried castor oil (drug store kind) by drenching the area around one affected hosta and closing the holes. That didn't work as the holes soon reappeared. I never did catch any voles or anything else (finger excluded)except for one in a nearby shed.
One reference I have states a high Big Short-tailed Shrew population to be about 25/acre whereas the six I caught equates to over 500/acre! I really don't know what to conclude from all this. My guess is the holes (photo below) were made by voles and soon after driven and/or eaten by an "exploded" shrew population.
Below is a photo of the holes I assume were made by voles. Do these look typical of vole holes to you?