Moles!! Boy oh boy have we had fun with them!! Became world war two with spooky and the moles last summer - they had their own trenches it got so bad!!
We tried every possible legal method known to man and mole, and the one that worked for us was recommended by a lady farmer. She told us to find the moles most frequently used runs, and push branches of gorse/holly into the run.
I can honestly say that it WORKED!! (they now happily reside in our neighbours garden, who now have the battery operated mole chasers scattered all over their lawn, instead of us!)
It doesn't kill or maim them, and won't destroy or poison your earth or lawn.
Hope this helps.
Debsy 'n' Spooky