I like the 2nd full image, but only because NR has enhanced the subject/background separation. I suspect you're not getting the most out of your NR program in terms of fine-tuning capability. I use Noise Ninja and found that, over time and with extensive use, I finally figured out how to make it do what I wanted. But I had to abandon any notion of 'automatic' noise reduction. It's a hands on, fine tuning process to get good results. There are at least six variables (2 each in contrast, strength of NR, and smoothness) plus sharpening.

However the biggest advance I experienced in learning how to do NR was when I learned that NR in one channel only, usually the blue channel, often yields far superior results - since, as fate would have it, most noise will be found (in the world of current digital sensors) in that channel.

So, in Photoshop CS2 I use the Noise Ninja plug-in first thing after RAW conversion. Well, not exactlly first - first I make a duplicate layer, zoom to 100%, switch to channels, select R, G and B one at a time and confirm which channel (95 out of 100 it's blue) has the noise.

Since I've downloaded Noise Ninja's camera profiles, the program looks at my image and chooses the appropriate profile which then has its effect. I toggle before and after with each change and I run through the variables listed above. When I'm done I activate the R and G channels to confirm if I like the result, or not. Often I wind up converting the layer in which I applied NR using the PS luminosity filter and reduce opacity to anywhere between 50 and 90% depending.

Another key trick I learned is that reducing the NR effect to something less than what my eye tells me is enough will allow me to sharpen the image later without creating more problems.

And finally, don't forget that you can create a new layer with a slight gaussian blur, de-sellect your subject, tune the opacity of your blur layer, then use the sharpening brush tool to selectively sharpen aspects of your subject it its layer (for birds - the eyes, some of the feathers, the beak etc.), flatten the layers... and never even have to use noise reduction!

Just a few thoughts that I hope are helpful. Great picture, by the way!