This Grey-headed Junco (Junco hyemalis) was bouncing around the base of a tree and conveniently hiding behind twigs, throwing off any chance of focusing correctly.
The Gray-headed Junco is one of the six subspecies of the Dark-eyed Junco (Junco hyemalis). Taken together, this group is one of the most common birds in North America. All six subspecies live in coniferous or mixed woods or patches of brush. They can be seen foraging on the ground or flitting from shrub to shrub.They live in Colorado year round. These pictures are from Roxborough State Park but I have also seen them at Odessa Lake in Rocky Mountain National Park. Their diet is mainly seeds (notice the strong beak), and insects and will often been seen foraging in groups on the woodland floor.