Poles of Tad

This week I noticed the coqui frog unknown frog eggs have hatched. There's a particular puddle I walk by every day on my way to school, and Monday I noticed it had tadpoles in it which weren't there Friday. This puddle is particularly large, and almost never dries up except in the driest of weather, so it's an excellent choice for frog eggs. But how do the frogs know? I've never seen tadpoles in any of the other, more transient puddles I walk by. Do they sit around watching puddles to see which ones dry up when there's a week without rain, and then pick the one that doesn't? Do they simply lay their eggs where they themselves came from (which doesn't remove the problem, just shifts it into the past)? Is there some other way they can just tell that this puddle and not that puddle is an optimum place to lay eggs? I can't imagine there's anything intrinsic to the puddle that would suggest that. How do they know?

Edit (4/17/11): I have had it pointed out to me that coqui frogs do not go through a tadpole stage, instead hatching directly as "froglets". In that case, I don't know what kind of frog those eggs belong to.

Edit (7/23/23): I've long since realized that they were probably cane toad tadpoles, so I might as well update this post.