We have had a cat problem and a fox problem, buggers are shitting on the lawn.
I have a sonic cat scare device and it works on Cats, one cat was sleeping in my garage so I got close with the device and
the fucker woke up and ran away, okay that was a little cruel but it proves it works. These devices are mainly solar powered
which charges the rechargeable batteries but need to be properly charged every so often. Some have a USB charge point.
Sadly the other device I bought to scare foxes didn't work on Foxes but now I have two that scare cats.