A superb subject for a critque. A spectacular looking bird in a very nice setting. Composition wise it's fine but a few simple correction techniques would turn this into a first class photo.
It's a shame about that small dead bush showing through the tail feathers, they would be much more defined without it's presence. At present behind the bird is a little messy, but I appreciate that you can't just say 'stand over there whilst I take your photo'.
I'd be inclined to use a little unsharp mask, which will improve overall clarity by improving sharpness and contrast in one go realy bringing out the plumage detail and quite possibly separating the bird from the background a bit more.
I can appreciate that Grouse only display just after dawn which can give poor lighting levels. This has led to muddy coloured snow and too much blue cast in the shadows. Also I detect what looks to be a little CA on the top of the beak which gives a soft area where it should be sharp. This is easily corrected using the hue/saturation tool in Photoshop and I think Qimage can do this too. It just needs the blues saturation reducing, which will add grey to the shadows and whiten the snow.
I often like to give a photo a Neat Image, which I suspect will benefit this shot since the sampling background of snow is a different colour from the main subject. The Grouse would no doubt stand out even better.
Overall I really like the shot and with a few adjustments it can realise it's potential.
I gave it a two star rating as it stands, but with those corrections I'd boost it to three going on four.