The head on aspect could'nt be any more perfect. the bird is looking straight down the barrel. Colours and detail lovely. I might have tried a crop with the bird exactly centered but that is a personal thing. Lovely image.
Nice head on shot here. Looks good for that ISO (not possible on my d850 by the way). Nice details as well. I would lower the yellows in the shot a bit. Not sure if you selected a cloudy white balance or not but I think there is a slight yellow cast that would easily be removed by lowering the yellows maybe 10-20 points.