Nice -- typical mockingbird pose -- they do have an attitude, don't they! Nice BG and I like the crop. I don't see the noise I would expect for ISO 3200.
Sharpness could be improved, which may be a limitation of that lens at the longest focal length. But maybe there is some softening from noise reduction? Or from very small camera movement? That shutter speed could be marginal for that focal length, depending on how rock-solid the tripod is. Or maybe there is less than perfect autofocus. Most cameras have some variability in AF accuracy. I find that if I shoot several shots of a subject, hitting the AF button for each, that often some will be sharper than others.
Another factor is thermal turbulence in the air -- you were pretty close here (unless this is a big crop) but on a hot, humid day, you can get softening from the air. I doubt is would be a factor for the distance to a small bird, though.
Nice pose! Thanks for bringing back memories of mockingbirds diving on my sister and me as we walked to school. Did you know that MBs can exactly imitate squeeky gates or the sucker rod mechanisms of windmills? They are wonderful birds.
The blueish sky cast seems to have muddied the red BG and blued the bird's color a bit, so I tried getting those back via New Adjustment layer> Levels to remove the 'noise' tails on all 3 channels. Try it!
Good catch, Jess. I think this is what you did -- but for each of the 3 color channels. (Correct me if I'm wrong!) That removed the color cast and improved contrast. Could be done several ways, like almost everything in the digital darkroom.