The genus Dendragapus, contains two closely related species of grouse that've often been treated as a single variable taxon; the Dusky Grouse Dendragapus obscurus and the Sooty Grouse Dendragapus fuliginosus.. In addition, the Spruce Grouse and Siberian Grouse have been moved to this genus. Description These are large grouse that inhabit highland regions of North America and Eurasia. The Sooty Grouse's found in the Pacific Coast Ranges and Sierra Nevada, and the Dusky Grouse in the Rocky Mounta… (More on Dendragapus)