You have done a great job with the exposure in this image. The grays and blacks both have great detail.
I think that two things pop out at me. The first is that the focus point looks like it was right behind the neck. This caused the tip of the beak to be just a bit oof. I think some selective sharpening will do the trick! The second is the reflection of another bird at the top of the frame. I would consider cropping a bit from the top and adding a sliver to the bottom. I think this would look great in a 16:9 aspect ratio.
I think you misunderstood Miguel - he meant to crop out a bit from the top where there is a distracting reflection, and add some more space on the bottom. I can see the image he's talking about, and it looks quite good. You've nailed the exposure here, and the HA is perfect. That red eye really pops.
You did a good job with exposure here, Don. You were obviously working hard to isolate your duck, and I think you did fairly well. I would personally like to see a tad more on the right and bottom, but only if you have it. No need to add canvas at this point IMHO.
You did a pretty good job on your focus here but I would add a little bit of sharpening to the head only.