ptarmigan

from WordNet (r) 3.0 (2006)

ptarmigan
    n 1: large Arctic and subarctic grouse with feathered feet and
         usually white winter plumage

from The Collaborative International Dictionary of English v.0.48

Ptarmigan \Ptar"mi*gan\, n. [Gael. tarmachan; cf. Ir. tarmochan,
   tarmonach.] (Zool.)
   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]