bobad, I don't know if you watched the video that I linked to earlier in this thread. It shows what seems to be very complex bird behavior. Here it is again: http://youtube.com/watch?v=BGPGknpq3e0
There are ants that cut up leaves and take them into their colonies as a substrate for growing fungus for food. If ants can evolve to harvest materials for, and tend to a future crop, then I can't see why birds couldn't have evolved to stock empty ponds.
