Voles in my lawn.
The snow has melted and my lawn is full of tunnels.
Uinta County Wyoming
Well, that does sound like typical evidence of voles (meadow mice, Microtus spp.) after the snow has melted.
It is mostly cosmetic at this point but if you are concerned about the voles, the typical snap-type mouse traps, laid perpendicular to the runway, seem to work the best.
If you have a garden or fruit trees in the yard, you should take some steps to protect them from voles. The publications listed below discuss several options for this.
Here are some documents that may also help:
Good luck and I hope this information proves useful.