Tomato plants seem to be a favored location for voles,
@heirloomgal . In my distant gardens, I was sometimes only made aware of their presence when a coyote would show up and dig them out.
My personal solution came to be a trickle of water down the burrow. It didn't seem to require a large amount, just a steady trickle for a good long time — like, maybe 90 minutes. The burrows are probably not very large but the voles are likely to be clever enough to
design them to handle the average rainstorm. A once-in-a-century catastrophic flood always seemed to work.
Steve