A nice image, a couple of points that I will submit as C&C, per req: The sky is rather bland; the use of a graduated neutral-density filter would have really perked it up. As well, the colours overall are slightly desaturated. The use of a circular polarizer would have given you a little more pop there as well. I would definitely remove the bird; this is not the sort of image where you want people to have to think about what something is. This is an image taken to record a scenic view. To me the bird simply looks like a spot. The composition is nice, but I would suggest zooming in a little more tightly on the falls; just a bit too much tree and not enough falls. Lastly, I would try a levels tweak to clear up some of the mist which is causing the top part of the image to appear slightly foggy. I understand that it's there, but I don't think in this case it's definite enough to add to the image.
Probably sounds like a lot of points, but really, they're all very minor. The image overall is very good, and can stand on it's own as-is. Those things I have mentioned are simply ideas by which you might, IMHO, improve an already good capture.
Just my $00.02 worth - your milage may vary.
~John