Timely topic, because the Houston Pond Society just sent around a question from someone asking how he could get rid of the noisy toads and frogs.
TxPond, I am sure it's not the sound of the waterfall that attracts them, but just the fact that there is a body of water. The toads and frogs can sense the water, without hearing or seeing it.
Sorry, if you're gonna have a pond, you're gonna have frogs and toads.
I would be happy to have even MORE. I'd sure love some frogs, especially tree frogs.