To emphasize the antlers, I added a Black and White adjustment layer, set to Luminosity blending mode.
Then adjusted the sliders to darken the sky and brighten the antlers. I masked out the unwanted changes to the buildings.
I added a new "merge visible" layer and masked the background so that I could sharpen just the antlers. Converting the layer to a smart object applied the mask, but allows editing the sharpening. Then I ran Neat Image on the background image to smooth everything but the antlers.
It is very easy to edit the Black and White adjustment for a variety of effects.

forum discussion: http://forums.dpreview.com/forums/read.asp?forum=1006&message=28610147&changemode=1
original image by Nomad71: