My pond has been full of bull frog tads several times in the last 5 years and I am amazed that I'm not sweeping young frogs off my house porch 200 feet away. I'm not sure where they go...one day I have thousands of tads, then they start growing legs and sitting on the pond's vegetation with a stub of a tail, then there mostly gone. By all rights, it would seem that I would have frogs EVERYWHERE, but no. Don't get me wrong, I still have a healthy population of frogs, but not thousands or even hundreds. I see exodus' of toads and some leopard frogs leaving the pond heading for dry grounds, but the young bull frogs must be getting eaten right out of the pond of abducted by aliens.