Hi Wendy - As one bird shot tyro to another I probably can't help much. You don't say whether you used a tripod. If not then that might be one way to start to get a sharper image, along with setting the focus point to exactly where the bird is, probably using manual focus. For PP, a sharpening technique other than Unsharp Mask might be useful. In the Gimp (which I use), there is a technique called wavelet sharpening that helps in this type of case. Another possibility is to use refocusing software. There are plug-ins for most software packages available for download. A third possibility is to try a small amount of local contrast enhancement. Finally, in this particular case, I would duplicate the layer and blend with Screen to give extra exposure to the bird itself. You might find that this brings out more detail.
PS Here's an attempt - hope you don't mind me pinching your shot. Pixel count is low - it would look better working from original.