Two closely related species (previously regarded as several subspecies of the Blue Grouse, see Zwickel and Bendell 2005) constitute the genus Dendragapus, the Dusky Grouse (D. obscurus) of inland mountains and the Sooty Grouse (D. fuliginosus) of coastal mountains. The ability of these birds to fly long distances is poorly known because observations of such behavior are at best serendipitous. In eastern Oregon, Anthony (1903) witnessed flights of both adult and immature Dusky Grouse from a mountain ridge to a nearby mountain slope and estimated the distance at “fully a mile and a half” (2.4 km). He noted that the flights were of “gradually descending” trajectory and seldom sustained enough “to carry the birds to the top” of the mountain to which they were flying even though the latter was 400 feet lower than the ridge. In coastal British Columbia, Zwickel and Bendell (2004, 2005) concluded that level flight in excess of approximately 2 km was unlikely for the Sooty Grouse because “few islands more than approximately 2 km from a source population are inhabited.” Furthermore, these authors described an instance “in which a hen that flew out over a lake came down in the water after approximately 150 m.