I agree completely with you and ditto everything you have said concerning stray cats in your yard. I have the very same problem. We don't own a cat but cats are in our yard every day. It's especially obvious in the winter when their tracks show up in the snow - across our front porch and around to the back (the same path every day) where my bird feeders and fish pond are. They stalk the birds, eat the fish, and use anywhere they please for an outhouse. I have 9 grandchildren and I don't want them playing in sand that has been used as a cat toilet. There was a young man who grew up across the street from us. In playing in his yard, he contracted a disease from feline droppings called "histoplasmosis" (I think that is correct) which can eventually cause him to go blind. I believe cats should be licensed like dogs and they should be kept inside. I don't know if it is true but cats have been said to be one of the major reasons for the decline of song birds. I will try the citrus to see if that helps.