gennepher
Oracle
Like you, @dunelm I have made the back garden pretty much cat proof from stray cats. But my back garden does back on to some ancient woodland, and I have foxes and badgers etc that leave little messages. The messages are very distinctive to the animal...I have moles too.
I am unable to stop the foxes leaping from garage roofs.
But the badgers that burrow under the fence are a menace. There is a family of badgers that insist on their right of way. They are often in the front garden, which is dug up on a regular basis. But I draw the line to them digging near my bungalow walls, or under the wall from front to back garden. The badgers want my frogs for supper. The frogs are in my ponds in the back garden. So I asked around for advice. I was told chicken wire. I placed chicken wire near and beside my walls and fence. I even dug some chicken wire into the ground. The badgers then stopped digging their tunnels under my walls into the back garden. I found that cats don't like chicken wire either, they cannot dig their little messages in, they don't like the feel on their paws. But I was pleased how successful the chicken wire was stopping the badgers digging, and into the back garden. The badgers decimated my frog population one year. But I have a breeding pond they always return to each year, and so my frog population built up again.
Other ideas are black cat silhouettes, metal ones, that you stick on the edge of the lawn, you can get a set of 3 fairly cheaply. But you do need to move them around to keep a stray cat on its toes. I have a stone cat with glass eyes (but the eyes need replacing again). And stray cats are wary of that.
My cats in the past have been scared of large birds, like buzzards. We have birds of prey here including buzzards. Some idiot a few gardens away was enticing a buzzard into his back garden, so it would swoop in for the meat/kill, I assume he was using meat. So my cats in the past fled indoors if the buzzard was near. One small cat of mine wasn't quick enough, she was on my garage roof. I saw it and couldn't get out to save her. The buzzard got her. Popeye is still very very wary. So, you know you can get quite big plastic owls, that move their heads (and I am assuming make a noise as well), a person across the road has one. She is not an animal lover. And the owl moves its head. Cats don't go in her garden. They give it a big wide detour.
The Scaredy-cat plant I have used in the past in the front. I was hoping it might keep the foxes away. I think it did. But it wasn't hardy enough to stand the winter here, so they died.
I understand half full plastic bottles in the border might work. The light reflection is supposed to deter. It's an old game keeper's trick. It might work with strung CD's or other
shiny reflective stuff.
I have a neighbour who stands guard at her window and charges out with a powerful water gun....but I am sure cats return to annoy her.
I mentioned cat silhouettes before and a large owl. Well, you can get them with realistic glow eyes. It's the glow eyes that is important. This works for badgers too. Maybe, if you are partial to gnomes, maybe some with scary glowing eyes, possibly battery or solar powered.
I have had infra red sensor LED lights in the front, both battery charged and solar. A couple I had. Cats and badgers don't get used to them in the same way as a continuous light.
I have had a lot of problems with badgers and I don't want them making my garden their home...but what works for badgers works for cats....
>^..^<