How can I keep stray cats away?
Thank you for posting this – I have the same problem (only I have an indoor cat who gets riled up when the feral cats howl). You may also want to see if you or neighbors have a food source for them – a garbage can that is easily burgled, for instance. I have heard that cayenne and other hot things can be harmful as cats bathe themsleves and can injure themselves severly by trying to get the burny stuff of their fur and faces (eek!
An easy solution would be to set up one of these motion-triggered sprinkler systems. They are designed for deer, but will work for most any pest. Set it up to aim at your porch… it’ll be like an automatic spray bottle that’s always on duty! It would do a much better job of permanently training “your” cats to stay away than you and an intermittent spray bottle possibly could. Of course you’d need to get one with a remote, or set it up so that the path to the back door doesn’t get wet, because I’m sure you don’t want to get doused yourself!