I just hope the critters don't think that this is just an automated drinking fountain!

Hi folks,
I have made "squirting" animal repellers previously, but found that sonic repellers are just as effective, and you won''''''''t get sued by the mailman for soiling his trousers.

You have to "tune" the ultrasonic emitter to the critter which "needs repelling". To protect a backyard pond from a crane which wants to eat small fish, you have to use a higher frequency than used to repel dogs or cats.
The owners of one German backyard that I sonically protected called me in some dismay. A large cat seemed immune to the sonic protector. I asked if the birds seemed upset by the large, lumbering old cat. No they said, why? I said that the old cat was probably almost completely deaf, and since the birds could sense that, they were not frightened of the cat at all. It could not echo locate the birds, let alone get its arthritic joints to make to capture a bird.