Ultrasonic bird repeller - not

Image cropped for size from the original at Reddit, where this comment by oilbird is relevant:

I study sensory systems (vision, hearing, etc) in birds and all birds studied so far are, with out a doubt, incapable of hearing ultrasound. In fact, the highest frequency at which they can hear is for all birds much lower than humans. Most birds don't hear almost anything above 6 KHz while humans go up to 20 KHz. Ultrasounds is defined as being above the human range, so no birds is ever going to be even remotely bothered by an ultrasound machine. Edit: Holy shit, talking about scams. This shit is almost 600 bucks. Says in their website is tuned to 20 KHz and humans can't hear it. as I said above, if humans can't hear it then it will not affect birds in any way, period.