The beds are pretty wet right now with all this crummy Seattle weather and he still seems to be doing his business. There are only 2 kitties that roam the neighborhood and I have never seen the other cat in my yard. We see this guy doing it and he likes to hang in my yard, so I really do think it is strictly him. The sprinkler thing might work. Next time he settles into to do his job, I will flip the sprinklers on and see if that works. Thanks!