That is a stunning photo! The colors and pose are beautiful. It might be nice to have a little more room on the right so that the tail isn't so close to the edge, though. If this was cropped, perhaps you could take the original and when you make your crop outline, rotate it a little clockwise so that the tail is a little lower, which might open up a little room for the tail. Then you could keep your proportions as is. Just a thought.
Nevertheless, without touching a thing, it's still a gorgeous shot!
Sharpness and angle look very good. Another vote for more room on the right, a horizontal crop might work, too. I wish there were not such a strong shadow on the perch.
You can use the horizontal type tool in PS to add a signature.
Hi Tiziano
You should post the exif details so those who view and want to comment can gather some thoughts whether settings etc may have also been changed to improve/alter the outcome. :)
Love the colors and as Jean said, a bit more room at the tail end would have been excellent. I think the way the bird is sitting a horizontal comp would have been more effective and you would have wasted less space around it.
Do you mean where to put signature? Or how? If you have photoshop, you can use the Type tool (T). Then merge layers once you wrote the signature and save for web.
Lovely colours, nice pose and good sharpness. As this was a portrait capture I would crop from above to lift the bird in the frame a little. Agree a landscape comp would suit better.