[2][3][4] These two taxa were originally regarded as separate species, but were considered conspecific for much of the twentieth century.
[5] whose results supported the earlier work of Brooks (1929)[6] who regarded the two taxa as separate species based on morphology, behavior and vocalizations.
The precise ranges of the two species are well-defined in the south, separated by extensive areas of unsuitable forest-free habitat, but somewhat uncertain in the north of the range of the genus where there is no separation; Barrowclough et al.'s study did not include these northern populations.
Adults have a long square tail, gray at the end (lighter in the sooty grouse).
[4] Their breeding habitat is the edges of conifer and mixed forests in mountainous regions of North America and Eurasia.