I've always used humane traps in the past. My cats used to bring the poor things in alive then release them to play with. But I had proof that they came back for more. One of their victims had a very distinctive white mark on its back. It was caught several times in the humane trap. I always released it down the field ten minutes' walk away and the following morning, yes... "Hello again Mr White- Mark!" In this new house I haven't yet had any rodent problem. (Not yet... Wouldn't it be funny if it was Mr White-Mark again?)