Nocturnal bird migration at full moon

10 dark spots on the surface of the full moon are in fact 10 birds!
f/8.0 1/3200 sec. ISO speed 800. 1 Sep 2020 22:49
One stop underexposed; some contrast enhancement added.
1000x1000 pixels. Sony A6400; 70-350. Manual focus
Width and height of the Moon itself: 783x779 pixels

What is the probability that birds appear in front of the full moon in a series of only 10 exposures? Close to zero, I would say. I only discovered them the next morning on my computer screen. One or two seconds earlier or later and they would have disappeared into total darkness. 

If the birds flew a few degrees higher of lower, I would miss them too. You won't spot them in the dark. If the birds flew directly towards the moon it would be harder to make sense of those clustered strange speckles. Luckily the birds did a nice fly-by. It looks like they are flying in one straight line. But they could fly in a V-shape. One cannot tell the difference. In reality the group could be bigger than ten. If there were only one or two birds in front of the moon, I would probably have missed them. If they were still further away from me, they would have been too small to notice at all. I doubt if the chances would be higher if they were significantly closer to me. It would be a hit or miss. At least, it would be less likely to see them all ten together.

Detail. 362x227 pixels (not scaled up)

There is just enough detail visible to conclude that they must be birds. Some have their wings up and some down. These black spots are darker than anything on the moon. I am not sure what species it is. It could be geese. Sheer luck that they entered my exposure. Thanks birds! Have a good trip! To whatever destination!

The position of the moon must have been southeast and the birds must be flying to the south or southwest (location: The Netherlands). They appear to be ascending. This seems unlikely to me. It could be caused by the orientation of my camera. I did not pay attention to that when taking the pictures.

Literature

• The moon determines when migratory birds head south. Sciencedaily, October 16, 2019
• The lunar cycle drives migration of a nocturnal bird. PLOS BIOLOGY October 15, 2019