White-tailed ptarmigan name "Tetrao (Lagopus) leucurus" by the Arctic explorer John Richardson in 1831. It was later determined that "Lagopus" had sufficient distinguishing features to be regarded as a separate genus and the bird became "Lagopus leucurus". Molecular studies have shown that "Lagopus" is monophyletic, with the rock ptarmigan ("Lagopus muta") and White-tailed ptarmigan being sister species. The position of the willow ptarmigan ("Lagopus lagopus") is less clear cut, it showing some genetic divergence over its wide range. The genus name "Lagopus" is derived from Ancient Greek "lagos" (λαγως), meaning "hare", + "pous" (πους), "foot", in reference to the bird's feathered legs.
Ptarmigan Pass (Sawatch Range) Ptarmigan Pass (Sawatch Range) Ptarmigan Pass (elevation 11,765 ft) is a high mountain pass in the Rocky Mountains of central Colorado in the United States. It is located on the crest of the northern end of the Sawatch Range, along the border of Eagle and Summit counties, south of Vail Pass. The pass is traversed by a jeep trail that is passable by four-wheel drive vehicles and on foot. 2WD vehicles will only make it to the summit from the west; the east side is rocky and boggy at times. The trail connects Interstate 70 east of Vail Pass with