There are lots of these stories, but most of them have one thing in common.  I had been out yesterday walking the woods at Blacklick Woods Metro Park, and had managed to get a couple of nice series of Woodpecker shots.  As I exited the trail at the nature center, I was engaged in conversation by another photographer.  He was a nice guy and we had a pleasant conversation.  As we were heading to our cars, I told him about my experience the previous evening at Ashton Pond, where I had gotten photos of a couple of Great Blue Herons and a Juvenile Red Tail Hawk.  I was heading over that way to see if anything was going on before heading home.  He decided to stop at the pond too.  When we arrived, we found the viewing deck at the pond to be somewhat crowded and noisy, and there were no birds in sight, of course.  In a few minutes everyone else left, and things quieted down, except for the two of us discussing equipment, past experiences and future plans for our photography and lives.  It was maybe ten or fifteen minutes into our conversation that we heard the quacking as the Male Mallard flew into the pond and landed right in front of us.  Neither of us had been watching, and both of us missed the shot.  Knowing that the duck would likely be flying out from the pond eventually, we started paying attention, following the duck through our lenses as he swam back and forth around the pond, appearing to be searching and calling for his mate.  I think it must have been an hour or so that we had been watching intently when we heard the drumming of a woodpecker nearby.  Both of us started looking for the woodpecker, and found a Yellow-bellied Sapsucker in a tree right behind us.  I couldn't get a clear shot through the trees, but I think my new acquaintance may have found a better location to shoot from.  As the Sapsucker flew away, we turned to review our photos of him when, without any sign or notice, the duck, which was within fifteen feet of us, took off.  I didn't have time to even get my camera to my eye before he was gone from the area of the small pond.  My new acquaintance may have gotten one or two frames squeezed off just before the Mallard disappeared into the tree line.  As I said to start with, there are lots of these stories, most with one thing in common.  And the thing they have in common is as relevant in life in general as it is in photography.  To take advantages of opportunities, you have to be prepared for them.