Sure is a good sign of a healthy environment when the little croaky fellas are happy. As for them water birds.... We had a fish pond in the backyard with about 150 goldfish and swordtails in it. Girlfriend came out one morning and said. "someones stolen our fish". I looked up on top of the shed, and there was a big grey Heron with a fat belly. Only 20 survived the attack. There was a net over the pond by next evening. Bl***y birds.
Bill