Another from my days shooting sparrows at McDonald's
It was a cold morning in November and this little sparrow was all puffed.
Liked the softness of the bg and the soft edges of the bird against that bg. A bit dark in the eye.
1/400"
F Number = F/6.3
Aperture priority
ISO 800
+0.33EV
400mm
I too like the BG and the bird looks great. As you mentioned, you could sharpen the eye more and brighten it up to get it better defined. If you cropped this tight I would recommend leaving more room on the left to get the two cut leaves into the image. That may necessitate leaving more room in front for a more horizontal crop. Nice work.