The exposure looks good. This image has the look of a large crop? Perhaps some additional USM would help bring some of the fine details back. I'd like to see a bit more room below, and a bit more in front of the sparrow. I would clone out the needles sticking into the frame in LLC, and might also consider cloning out the horizontal one below the bill - it just seems out of place. Thanks, and keep them coming!!
Good points by Daniel. I would expect a sharper image out of the 300 f/2.8 unless it's a heavy crop. Since you were already high-key, I would have pushed the ISO a little higher to get a faster shutter speed than 1/250. That would have helped with sharpness. Thanks for posting!
Thanks guys, and no its not much of a crop, almost full frame. I need to calibrate the lens to the body, this was on a tripod, IS was on and still not as sharp as it should be.