In years past, there is a bat that will come out right after dusk and fly over and around our pool several times. We can't really seem him all that well, but he moves too fast and makes too sudden of moves to be a bird. It looks pretty neat, especially if the pool light is on.

We came home from being out one day last summer to find male and female mallard ducks swimming in our pool. I guess they were making a pit stop, they haven't been back since.

Otherwise, I've only found dead lizards in our pool so far.