Voles:
Voles are small 4 to 5 inch long rodents. Voles are often mistaken for mice as they are close relatives to lemmings and hamsters. Vole populations tend to grow big and then die off naturally being cyclical creatures.
Lately the voles have been able to better survive winters meaning that they live till the next round in food during the spring rain. This is bad because longer life spans is resulting in more voles more often.
voles can be harmful by destroying garden, lawn, or trees in some cases. Voles can also be harmful in the same ways as mice: link or something to the page about mice or something.
One way that people have found to minimize voles in gardens is to essentially dig a mote around your garden. The reason why people do this is because voles hate running on bare ground and so if you make a ring of bare ground around you garden then they wont want to cross it.