Lagopus mutus

Ptarmigan Ptar"mi*gan, n. [Gael. tarmachan; cf. Ir. tarmochan, tarmonach.] (Zo["o]l.) Any grouse of the genus {Lagopus}, of which numerous species are known. The feet are completely feathered. Most of the species are brown in summer, but turn white, or nearly white, in winter. [1913 Webster]

Note: They chiefly inhabit the northern countries and high mountains of Europe, Asia, and America. The common European species is {Lagopus mutus}. The Scotch grouse, red grouse, or moor fowl ({Lagopus Scoticus}), is reddish brown, and does not turn white in winter. The white, or willow, ptarmigan ({Lagopus albus}) is found in both Europe and America. [1913 Webster]