In recent years, interest in the presence or absence of Ruffed Grouse (Bonasa umbellus) in Colorado has increased. This interest was heightened with the reported observation of a single Ruffed Grouse near Hayden, Routt County, in 1971 by P. Lehner (Martin et al. 1974). Subsequently the Colorado Field Ornithologists Official Records Committee accepted the 1971 sighting and a 1947 observation of a female with three young near Hermosa Park, La Plata County (Reddall 1976). Ornithologists have not been alone in their interest in this species, as hunters and conservation agency personnel have periodically discussed prospects for the introduction of Ruffed Grouse into Colorado. Presently one land management agency is justifying in part its program of Quaking Aspen (Populus tremuloides) manipulation in Colorado on the basis that it will benefit Ruffed Grouse. In view of this interest we felt it was timely to clarify the known status of this species in Colorado. To fully understand the complexity of the situation it was also necessary to review the status of another forest dwelling Colorado tetraonid, the Blue Grouse (Dendragapus obscurus), and compare important characteristics of the two species.