Nice black/white exposure and really interesting perch.
I'd probably crop the bottom a lot harder, so that the entire knob in the bottom right-hand corner was removed. I have mixed feelings about the background. It seems a little distracting, but it also seems very interesting as compared to a more even background. I'll leave that one to people with more experience.
Decio, I agree with Paul on the cropping from the bottom. Also, the bird's head is turned slightly away from the camera sensor...it's really better to try to capture him either looking towards you or at least even with the sensor plane. I definitely think you could lower your aperture for a softer BG and still get the entire bird in focus...so give that a try next time.