Hi Bob, sorry, just added the exif; I know about the room at the right side. Personally I like the birds to have some room :-) I know, that's may be just me :-)
Nice pose, subject, sharpness, BG colour. There appears to be a lot of banding going on in the BG though. Maybe select the BG only and run NR a few times?
With f/5.6 being wide open for this lens, and with plenty of shutter speed available you could stop down for added "sharpness" especially with the 100-400's reputation (most lenses are not at their best wide open anyhow). Very nice though, and I like the space at right...
Great details despite the harsh light. I like the angle and composition and would only crop a bit off the right to get rid off the bright spot. The banding is probably just due to the compression. You could try to desaturate the greens a few points.