There is some noise showing up, esp. in the reds of the tail. Could the bird have been underexposed because of the brighter background, and then the noise crept in as you brought up the bird in post? I wouldn't have expected this much noise at that ISO.
The eye looks a bit lifeless because of the lack of a catchlight.
Nice to see the red shafted version. We only have the yellow here in Michigan. Thanks for sharing.
These are tough birds to get images of. At least here in NY. I think Randy hit the nail on the head with his comments. A small catchlight would make a HUGE difference.