Last night while shooting the moon I was attempting to capture geese crossing the moon. I was only partially successful and had numerous parts of geese getting silhouetted by the moon. So i decides to take a composite of several images to accomplish my vision.
Run some noise reduction...you've got a lot of BG noise going on.
Also, the geese are really more dark gray than black. I'd select them and drag the tones down using levels. I'd also selectively sharpen them just a bit.
As for the comp, consider taking a little off the top and right - you've got more space than you need and if you do it carefully it won't feel too tight.