Watering with mice

BMG's little brother was helping me water the plants yesterday. He kept playing with the watering can and saying there was something small and furry inside with a lovely long tail. I thought he was just pretending, until he tried to tip it out on my head, when I decided I had better take a look. Turned out there was a dead mouse in the watering can .... not exactly what I want on my head! Only tiny and quite sweet really. I've seen one out during the day recently, eating the bird food that falls off the feeders. I don't mind a mouse, just don't want rats!!