Voles are a type of mice that live in burrows. They don't make mounds of dirt at the tunnel mouth. If you live in an area that has frost, walking around when it is frosty is a way to find the active holes. The frost at the mouth of active holes is melted because of the heat from the voles inside.
Moles are hunters that eat worms, insects, grubs and such. They dig two types of tunnels. The shallow ones that often hump up above the surface are "hunting" tunnels, which are where their food source lives. They also dig "deep" tunnels for travelling and refuge. The hunting tunnels are mostly for one-time use, and the deep tunnels are reused often. If you use traps, they should be placed in the deep tunnels. Moles leave round, almost hemispherical mounds of dirt that they remove when making their tunnels. If you trap or kill moles, other moles often move in, using the old deep tunnels.
Gophers are rodents that mostly eat roots. They push out dirt from the mouth of their tunnels in a way different from moles. The tunnel mouth is angled to the ground surface, and the expelled dirt it pushed out of the mouth to the side, instead of mounded straight up. The tunnel mouth is closed up with dirt when not in use, so an open hole with fresh dirt spread out from it is an indication that the gopher is active and nearby. I have a truck built for forest fire protection on our tree farm. It has a high volume, high pressure pump and a 2,000 gallon tank. When I find an active gopher hole, I bring the truck over, put the 1" fire hose in the hole and start pumping with the engine at idle. Pretty soon a soaking wet gopher pops up stunned and shaking. You can just walk up an dispatch them easily, because they are too disoriented to try to escape. A garden hose will not deliver enough water volume to accomplish this.
Some cats and dogs will hunt and kill moles. They seem to catch them in the hunting tunnels. The same goes for gophers. Cats seem to be better at this than dogs.
