Nikonian72 wrote:
Successful nature photographers tell us that it is critical to have insect, bird, or animal eyes in focus.
Upon download and enlargement, the water ripples behind your bird are in focus, but not the bird's head nor eyes.
Exif data states: ISO 400, 1/250-sec at f/6.3. Shutter duration is short enough to freeze subject movement, but DoF is behind subject.
I'm going to disagree with your statement that a shutter speed of 250 is adequate to freeze subject movement in this image. That bird looks like it was moving pretty good through the water and the photographer was likely panning along with it causing additional lens shake.
I expect in a case like this a shutter speed above 500 minimum would be safer.
The lighting does not look very good so that would require an increase in ISO which is not ideal but either you do what you need to do to get the shot or you come back another day when the light is better.
On a seperate but related note, I don't think any part of this image is truly in focus.