Ken,
We had about 20 cats from some of our irresponsible neighbors making a unbelievable mess about our place. I like to keep peace with the neighbors whom, I for the most part enjoy & for years we had "house" cats too, so tried a long list of so called humane measures to solve their invasion. In the long run nothing on that list worked & fortunately for me the state of Wyoming is I believe the last one left that allows cats to be treated the same as raccoons or skunks if on your property. Also fortunate for us the raccoons & skunks, which we have a plenty, have never been a problem like the cats. My cat problem has been solved, but no doubt will return & have to be dealt with on a on going basis. I won't describe those solutions here, but will be glad to at the Cathlemant Gathering & I think you will enjoy the tale.
Jay