Posted: 27/05/2013 at 21:48
Mice are often a problem to gardeners, digging up seeds and eating seedlings for a start. My winter onions were almost entirely eaten from 150 to now about 30. Although that was probably because of the long cold winter we're still coming out of.
It's up to you how you deal with them really, maybe if you can identify the species you'll be able to work out whether it'll be a problem for you. I suspect though, you will probably have to do something about it (and I admire people who say there's just one for their optimism).