Hi Rob,
I like these little guys. A few points to consider...first I would start off by cropping the negative space from the right and moving both the subject and tree branch over. they are too centered in frame. Then you will add more canvas on the left side of the frame. The light angle coming from the side is also throwing a shadow on the bird's right side. Its best to have the sun at your back so your subject will be evenly lit. The bird looks soft in the feathers on the head area and the breast section possibly due to sharpening. Also the eye is soft too. Would selective sharpen the eye...keep them coming, looking forward to more...:cool:
Agree with Gus and can offer a couple of suggestions. I like how you raised the ISO for shutter speed, would further use the lens wide open to increase further, at 1/160 might have had some camera shake leading to softness. Also try placing the af point right on the eye !!
One other setting you might consider is the color space. Can switch to sRBG since it will have no effect on the RAW capture but will look better in your LCD, also the highlights will blow earlier since its a narrower space, safety margin !!