Ian, I think the biggest thing you're battling here is the harsh quality of the light. You've got a great pose and some nice detail but the light feels really stark. I'm also noticing that the curved area of the head/neck are not quite as sharp as the rest of the bird - it could be those feathers are softer but I think a little more sharpness in that area might help.
Do you remember what time of day this was taken? I also like Bill's idea of desaturating the blues a bit - they really pull my eye away from the bird.
You might try a reverse "s" curve for the lighting issue but I think that's only going to help so much. I also tried a "glow" filter/action on the BG and that seemed to soften the light a bit as well, although it wasn't the most natural looking solution.
Thank you folks. Actually, Jules, this was taken yesterday just at sunrise. I wonder if the harsh-look is from oversharpening as the light was certainly not harsh at the time. I agree about the blues -- I'll go back and work at those again.