I wrote this a few years ago but it might be of interest:
SONIC DEVICES
These days it’s easy to obtain sonic devices, usually operating on pitches only audible to animal ears, which the makers claim will deter a variety of animals such as cats, foxes, rodents or deer from entering your garden or other places where they are not welcome. Some of them, it must be said, seem to be quite effective although different animals are most sensitive at varying frequencies.
Not so long ago, though, they were not readily available in this country. A friend, recently returned from the USA, presented me with an early model picked up as a curiosity in a shooting store. It was called the ‘Animal Lover’ and was intended to be mounted on a car to prevent animals from running onto the road in front of it. Wired to the battery, it was only activated when the vehicle was running.
I must admit that, while sceptical, I was intrigued by the concept and decided to test it. The device was fixed to the front bumper of my old Landrover and, as an added refinement, fitted with an on/off switch so that I could activate it when I wanted to from the dashboard.
The next morning I toured my stalking grounds where we never shot from, or near, vehicles, and as a result the deer were quite relaxed in their presence. Seeing a roe doe with two kids, I stopped the Landrover and though I’d see what effect the Animal Lover had. I flipped the switch; the kids ignored me completely, and their mother continued to stare in my direction, chewing occasionally on a mouthful of freshly cropped herbage and showing no concern.
Undeterred, I tied it again on several more animals with no effect whatsoever. Discounting the gadget at a useless gimmick and deciding to get rid of it, I drove home to find the family cat, a large, battle scarred tom which brought home fully grown rabbits to play with and which the local dogs gave a wide berth, sleeping peacefully on our doorstep. Idly I switched on the Animal Lover with unexpected results; the cat went from deep slumber to three feet off the ground in one movement and fled at speed. It was not seen again for several days.
I removed the device and decided to keep quiet.