Very nicely photographed Bill. Bird is perfectly positioned, nice reflection and great BG.
I would like some detail in the black head, but exposing for this would almost certainly blow out the highlights of the bird's breast. I spent a week photographing loons and I found it difficult to consistently get great exposure of both the highlight and shadow areas of the bird. I often opted to expose for shadow detail and to accept some blown highlights in the breast area. In a short while I'll post one of my loon photos to illustrate.