I feel I should warn you about humane mousetraps as my parents had a lot of trouble with mice at one point and because we are 3 out of 4 in my family are fluffy animal-lovers (that is to say, we love fluffy animals - but not in the Biblical sense) we decided on humane mousetraps.
Here is the scenario:
1. Set humane mousetraps.
2. Catch many mice. Release into wild, pretty damn far from the house.
3. Continue to have mouse problem.
4. Dad decides to mark one mouse by painting its tail with Tippex (whiteout to you, I think?), then releases into wild, pretty damn far from the house.
5. Mouse returns.
6. Repeat steps 4 and 5 until all remaining members of family decide that killing mice is probably preferable to wasting energy, food supplies and money on them.