As you are thinking about closing up your cottage for the season, don’t forget to make sure you seal things thoroughly. Mice can fit through surprisingly tiny openings.
You can also reduce the likelihood of unwelcome guests by making sure that there are no sources of food or water for them.
If you’ve had problems with mice, you might also consider leaving bait stations for any that do manage to get in.
It’s also a good idea to make sure outbuildings and boats, if any, are secured against raccoons, and that you’ve dealt with any damp wood or leaks.