"I modulated my remarks when I found out they are campers who leave nothing on a trip to the outback. NOTHING. They pack EVERYTHING out."

I do that, too. However, rodents that want to move in--had a plague of deer mice once, and they are disease carriers--got the fast treatment.

I tried humane traps and got called away one time for a few days. Came home to find a barely living field mouse about to expire. He'd/she'd had no water for that long--since it got trapped. I felt so sorry for it I got it some water. It revived in about 20 minutes. I took it to a field about a mile away and released it. Since then, the old snap has been the one.