Another moment

Earlier tonight, i went for a stroll outside to take in the night air and enjoy the full moon.  As i stood, watching a possum clamber along a fence top, i heard a faint, plaintive sound from the sky.  I knew the sound but couldn't place it.  The call came closer and i strained my eyes to try to make out a shape against the dark sky.  Then i heard a rhythmic swooshing of many wings, as a flight of swans came into view, crossing the moon in a perfect diagonal line, silvery feather tips edging the black silhouettes.  They passed from sight as quickly as they had appeared, leaving only the odd plaintive cry receding into the distance.