My boyfriends mother swears by putting plastic
2 litre bottles filled with water around the garden
and in flower beds. She nevers has this problem
now. Hope this helps ;-)
Cats hate the smell of oranges so put pieces of orange peel in areas that they frequent. Smear your fence with orange oil.....choose big oranges and squeeze the skins with the outsides together and the oil will ooze out!
Squirt the little intruders with a water pistol, cats hate getting wet and won't come back if you aimed at them a couple of times. It may sound cruel but it has worked in my garden.
Get some thorny twigs, eg; rose, berberis and lay them on the ground all over the garden. They don't look unsightly and are cheap and easy to replenish.
If you can the water pistol is definately the best option. I've got cats and anytime they misbehave we simply spray them with water, they never consider doing it again!!
If you don't have any cats yourself there is a wonderful gadget you can get from garden center's or DIY stores that makes a noise that only cats can hear, they don't like it so avoid the garden. You can get it mains or batter operated. Its been the only thing that has worked for me.
If you have cats yourself then the above it not suitable.
Except some people can hear this contraption...if you have good hearing yourself then I don't recommend this option as you may be able to hear the awful noise it makes. Trust me, it's worse than nails down a blackboard.
Orange peel, cut up oranges keeps them away too. Some dislike Human hair, works on foxes too, the hair that is. Well not the fox, they'd look rather weird wearing a mismached toupe, oh I digress, long day here. :-)
Strange you say you can hear it, I have very sensitive hearing, due to a chronic illness and mine it right by the back door. It does not bother me or my family or neighbors, I checked as I live in a quiet area and it was one of my major concerns. There are different makes though maybe that is the reason.
Another tip though I have not tried it but it has been said to work it Lion dung, you can buy it of the Internet.
Good luck!