I have once made sounds that are loud in both audible for human and ultrasound to try to scare a hedgehog on a feeding place.
It was because someone had an idea to put ultra or infrasonic sound on robomowers to make hedgehogs move away.
From using a ultrasound detektor for bats I know that blowing sounds with hard pressed lips as well as key shaking makes a lot of ultrasound.
It made the hedgehog almost curl up, but anyway it ended up walking towards me.
That makes me believe that ultrasound wouldn’t deter a hedgehog.
