I like the way the perch is raised in the middle. Sharpness is good, and the BG is nice. The whites have a blueish cast on my monitor. You may be able to pull a little more detail out of the blacks in post.
Wow, I liked the shot up top, but then I scrolled down and saw Doug's repost. Even better. Giulio, I'm digging your setup, man. I've seen that 400 f2.8 lens in action, and I like it. You've got some real speed and low-light capabilities with that f2.8 lens and the D3S. Looking forward to seeing more of your work.