Tony, moles are strongly territorial and, unless you have a huge plot, for 'moles' read 'mole'. Other than making a bit of a mess is it causing any damage? I have one that roams around my plot throwing up mole hills, other than burying a couple of young broccoli plants, it's never done any significant damage and I'm happy to live with it. Moles feed almost exclusively on earthworms so, in that respect, they are detrimental, however, I suspect that, like most animals, they will live in balance with their environment - their demands in terms of earthworms will more than be made up though the worms breeding.
If you do need to control your mole there are various types of trap available, the most common types are 'scissor' and 'half barrel'. Catching moles with them is, however, an art form!
Rick
