The colors rock! Wish for more room in front of the bird and yo u could have gone to iso 800 in that situation to get more shutter speed 1/320 is borderline for making sharp images of moving ducks.
And also a lower angle could have been nice, but you would loose that beautiful water.
Welcome, John and congratulations on the new equipment. The colors of bird and water are very nice. I would prefer a crop with the mallard swim into the frame and a lower angle.
I really like the colors and details on this one. The composition could be a little more to the left, allowing the bird to have more room and like Fab said the lower angle could help this image as well.