I've been hearing frogs jump into the water when I walk around the pond shoreline but they seem to be invisible to me. I know it is frogs because it is the same sound that I've heard when I watched frogs jump into the water (the only snake I've seen jump in the water didn't make any sound at all, birds are too coordinated to just be startled and fall, and the water turtles can't jump). The only kind we've ever introduced here are the leopard frogs from Juan's pond and although we have seen a couple through the years, for the most part they immediately disappeared into the reed jungle. And why are they so shy? We never bother any of the animals. Even Bill enforces animal sanctuary rules to at least the bottom of the berm (for all small fresh-water pond animals except large water turtles.)