Great pose and BG. As for the reds, you could selectively desaturate them a few points. I might crop a bit top and bottom and would apply curves or S/H by selecting the bird only, using the magic wand tool to avoid halos. The BG looks a bit noisy.
I agree with Axel but dang! That bird is tack sharp and beautiful! Your BG is probably a bit noisy because of the higher ISO. I really try to keep mine below 400 if I can help it and really prefer 200 or lower.
One fine image Jack !!!! Since you had all that speed might have gone for a lower ISO Still even as presented love it !!!!
The reds is something with all digital captures Most cameras will over saturate the color Yellows are also affected !!! Just bring down a notch Big Congrats !!!
Image is quite dark, and I don't know what your camera's histogram is showing you. But your presented image is not showing much data in the rightside histogram boxes (same even in the reds). I suspect that you can try letting in quite a bit more light before anything blows out. I think your late afternoon, or cloudy conditions would also be helpful.
nice repost Jack.
My experience shooting blackbirds and grackles is to get a slightly overcast day.
Too much sun will cause highlights with a lot of dynamic range.