Once in a blue moon...the geese fly in front of the moon.
Ok, ok, I know that the "blue moon" ended at midnight last night when the new month started.
Still, when I saw it this morning at sunrise and heard the geese honking as the left the lake for the farmland to the South of Denver, I knew that I had a good shot at this shot. They fly by in waves for about 45-minutes. I just sat in my car and waited for a group to fly by at the right height.