As the pond I built behind my house goes into its second year of existence I remain impressed with the number of creatures that have taken up residence. There is a frog that croaks throughout the night and a dragonfly that jealously patrols the water's surface by day. Where these creatures came from is a source of puzzlement to me. There are no other ponds near my house, however there is a small stream in the deep valley that runs down from the mountains. Somehow, they discovered my pond.