Perhaps Thomas will be in a better position to explain.
From here, the bird isn't actually upside down.
We are seeing the upper wings/back and a strong clockwise rotation of the birds head to catch the fish (and tail to stabilise/assist the bird during the twist).
It is such an amazing rotation of the head that you might predict that the bird has to roll 360 degrees to complete the manoeuvre.
Great photo.
Eric
[ Last edited by EricB at 26/12/2012 04:17 ]