Hi Raul
Nice pose and head angle. I can almost hear the song.
Im guessing this is quite a large crop as Im seeing some sharpening halo LHS of the bird and quite a bit of noise (could be my eyes though - its late and I've had too much coffee). I would try to regain some image quality by going for a larger crop. Sparrows are small anyway so would work with more room left right and top. I would see how it looks with the bird reduced to about half its current size in the frame.
Good observations by Stuart. I would certainly revisit your sharpening to see if you can eliminate the halo effects and still maintain adequate image sharpness. If not possible, then smaller in frame is an option.
The perch is interesting but pretty massive for this little guy, and including more of it with looser framing might over power the bird. You could also look at toning down the luminosity of the stump a bit to reduce its visual impact.
Good singing pose and I like the comp. As mentioned, the IQ seems to suffer - particularly the face and the halo mentioned along the breast. These guys should be showing up in about a month's time up here - your image makes me want Spring back SOON!