Good job on getting the reds right. These are pretty birds to see but trouble for me to not blow out the reds. It looks to me like if the cardinal stood strqaight up, he would be out of the picture -- if it were mine I would take some off the bottom and add more to the top.
Stuart, not sure what lens you were using, but could you have opened up more? It would have helped your shutter speed, ISO, and blur the background more. But you did well getting a sharp shot as such a low shutter speed!