and deer feces:
Vole damage looks like runways or shallow tunnels in grass. What kind of tracks do you have--any deer tracks?
Maybe try the electronic deer repellent shock pole. Bait with an apple. When his nose touches the two wires, 15,000 volts. Three AA batteries not included.
I suppose armadillos are out of the question, but skunks and racoons are still possible. check for grubs.