Hi Ralph. Welcome to ATP.
Here is a link to the same question by another ATP member. And a link to other vole problems by folks here. I do hope they are of use to you. I do not have a problem with voles, as we have cats and a number of owls, hawks, kestrels and eagles here.
The thread "Voles!" in
Ask a Question forum
http://garden.org/ideas/view/f...
http://garden.org/ideas/view/d...
There are more, and you can find them by typing voles in the search bar in the upper left hand corner of any page.