Hi Axel, you are very observant :) I didnt think the bird was very sharp either but I do have trouble telling what other people call sharp and what they dont consider sharp, so much so that I often wonder if a lot of images are actually over sharpened and I get confused (easily done). I think the point of focus in this is actually forward of the bird but wanted other peoples opinion about the sharpness and I think you have clarified that completely - thanks :)
BG doesn't bother me... it is a nice environment shot. I do agree with the softness of the plumage. The red berry is a bonus, and really adds to the image. Good work on getting the catchlight too.
Tell, it looks like your point of focus was actually on the perch, just below the feet. Those leaves are in perfect focus, and are pin sharp. A sign of over sharpening is when you see the tiny shiny bits on the subject, I call it crunchy bits. Hope that helps.