Beautiful image!
Light, pose and background works well together and makes the image complete.
The pose makes the empty space over the birds head and on the right side look a bit "big".
I would try cropping the image slight on the right side and on top. The body would be in center and the neck and head up in the right corner. In that way the bird makes a smooth S to follow.
The image works very well as it is but there could also be an alternative version.
Critique in english is hard. Please ask if you don't understand what I meant.
I really like the preening behavior you captured. The background is nice and the detail on the bird. My eye is distracted by the little blob? at the bottom left. Is that part of a reflection?
Superb low angle, exposure, sharpness BG and pose. Loved the crop a lot. Thx for sharing. If it fits your ethics, then you can clone out the OOF stuff in FG.