I removed some brown OOF patches from the water that I did not know what they were. Maybe OOF Mallards or just reflection.
I find that a cleandn blue gives a better chance to the bird to show.
I might include the one with the brown spots as a "comment" later.
Thanks for looking.
Canon 1D MIV
Canon 500 f4.0 L IS
Manual Exposure
ISO 800
f 5.6
1/2000 s
Nice light, colour and detail on the duck Karl, I also like the OOF unobtrusive background. It could have done with more space at the top of the image IMO.
Very nice detail throughout the Mallard. I like the clean background, there is just one spot in front a little above the bird (about a head length's away), where you can see just a bit of an artifact (or at least that's what it looks like to me).
A minor clean-up on a white spot on the left wing, and it's a winner.
Beautiful flight shot! I also love the separation from the blue water. In addition to Miguel's suggestion, and it's optional, lighten up the stuff near the left wing. Also, you need to clone/heal the lower left edge of the frame.
Gorgeous colours, and the slightly banking pose adds some interest to the flight pose. I could see a version with the subject a bit lower in the frame.