This looks like one from your day on the lake with me. I like the close up portrait and the way you captured the colors on the head and back. The dark areas are lacking in detail and there is a bit of noise in the bg. Did you sharpen the bird selectively? If not that would reduce the bg noise. If so, blurring the bg a bit would help. I like the other Grackle portrait we looked at on your PC better.
A question, Jim: The black chest isn't blown (the RGB is about 10,10,10) so do you think the detail loss is due to DOF? It was 400mm @ f/5.6 from about 10 feet.
There just wasn't enough dynamic range to get the bird exposed properly and get details in the dark areas in shadow. You may be able to get a wee bit of detail by applying the SH tool to the black areas, but it would have been better to try for a position where you got even lighting on the whole bird. That is why I liked the other one better.