never happen in a million years
And therein lies the sticking point.
If we're talking 1 year, no, ponds will probably not stock themselves. If we're talking 10 years, they probably will.
Are birds smart enough to stock ponds? No, but that's not the question. The question is, can birds, turtles, etc. incidentally transport fish or fish eggs into a pond. Given enough time, the answer is yes.
It's amusing that people scoff at birds "intentionally" stocking ponds, yet they doubtless marvel at their ability to migrate 8000 miles unerringly. Since I've never observed, or seen reliable documentation of that behavior, I don't know if it's real or not. I do know that fish and birds are known to exhibit far more complex behavior than "self-stocking"!
