Good clean BG and your timing and exposure are spot-on, however the bird flying away and the focus on the perch rather than on the subject hurts the image. If these guys are anything like our chickadees then they come back readily for food, so perhaps you'll get another crack at it!
Daniel hit the main points. You can post the images at up to 1024 wide, which will show your image to greater advantage and allow us to do a better critique.