WOW!!! What I love about this shot is the contrast in color of the birds in flight against the dark background and the standing dark-colored geese against the white snow. Very impressive!
It is quite clear, once you follow the arrow. Ironically, the wing position of that particular bird is the most beautiful of all. I think you caught it at the moment its wings were in the most extreme forward position before pulling back to repeat the stroke. The way the flight feathers splay out is quite stunning. This shot is like a study in bird flight. Very nice.