 Why is the narrator the only one who notices a flight of volplas soaring slowly across the full Moon?
Volpla By WYMAN GUIN Illustrated by [Transcriber's Note: This etext was produced from Galaxy Science Fiction May 1956. Volplas at last. Yet I had always been so sure I could create them that I had been calling them volplas for ten years. I had called them volplas since the day old Nijinsky's elongated arms and his cousin's lateral skin folds had given me the idea of a flying mutant. When Nijinsky saw me looking at him, he started a little tarantella about his cage. Again in the laboratory, I entered the metabolic accelerator and withdrew the intravenous needles from my first volplas. It would be several hours before they would begin to move, to learn to feed and play, perhaps to learn to fly. Meanwhile, it was clear that here was no war of dominant mutations. I thought, "All this and three volplas, too." I kissed her until I heard rollerskates coming across the terrace from one direction and a horse galloping toward the terrace from the other direction. Outside this little town, I found a litter of flat stones that had young black-snakes under each slab. Except for the face, chest and belly, they were covered with a soft, almost golden down. The spars had been common to the basic colony for years and were the result of serial mutations effecting those greatly elongated fifth fingers that had first appeared in Nijinsky. No longer jointed like a finger, the spar turned backward sharply and ran alongside the wrist almost to the elbow. Suddenly, as I teased the male volpla, this happened.
 Because people generally only notice what they look for and would dismiss the phenomenon as something else.
 Because volplas are fictional creatures and people do not believe they exist.  Because other witness believe this was ET with  a little boy riding his bicycle over the moon.  Because people generally only notice what they look for and would dismiss the phenomenon as something else.  Because it is nighttime and everyone is indoors.