I had, key word, "had" tremendous vole problem. They were eating the root ball from some shrubs and other greenery. I had about 15have only 2. Weather they are dying or leaving I don't know and really don't care as long as they are gone.
I have gophers in my front and backyards. MoleMax works for me. I understand it can be a bit expensive to use since you have to keep reapplying it after three months under dry conditions and more often if raining heavily. So for California, it works quite well. While living here for 34 years, I have never had such active gophers as lately - due, we understand, to construction in a nearby vacant field. MoleMax is great because it is safe with with pets and children.