WHITE-TAILED PTARMIGAN. 
125 
obtained marked with undulated, slender, ash-grey, and dusky lines, in any 
degree approaching those characteristic of the British bird in its autumnal 
plumage. The bill of the Rock Grouse is shorter and thicker than that of 
the Scotch Ptarmigan, although the reverse has been alleged. 
WHITE-TAILED PTARMIGAN. 
Lagopus leucurus, Swains. 
PLATE CCCII. — Adult in winter. 
This pretty little Grouse is an inhabitant of the Rocky Mountains, where 
it was found by Mr. Douglas and afterwards by Mr. Drummond, who sent 
several specimens to England. * It is said to extend as far as the Columbia 
river, but has not been observed in that region by either Mr. Nuttall or 
Mr. Townsend. All that is known of its habits is, that they resemble 
those of the Ptarmigan. Mr. Drummond states, that this bird never has the 
black stripe from the bill to the eye, so conspicuous in the males of the other 
species. My figure was drawn from the only specimen now in the Museum 
of the Zoological Society of London. 
Tetrao (lagopus) leucurus, Swains. White-tailed Grouse, Richards and Swains. 
Fauna Bor. Amer., vol. ii. p. 356. 
White-tailed Grouse, Nutt. Man., vol. ii. p. 612. 
White-tailed Grouse, Tetrao leucurus, Aud. Orn. Biog., vol. v. p. 200. 
Adult in winter. 
Bill short, robust ; upper mandible with the dorsal outline curved, the 
ridge and sides convex, the edges overlapping, the tip decimate, thin edged 
and rounded ; lower mandible with the angle short and wide, the dorsal line 
convex, the back broadly convex, the sides rounded, the edges inflected, the 
tip obtuse. Nostrils basal, roundish, concealed by the feathers. 
Head small, ovate ; neck of moderate length ; body full. Feet of ordinary 
length, stout ; tarsus and toes feathered ; the first toe very small, the middle 
toe much longer than the lateral, which are nearly equal. Claws slightly 
arched, depressed, broad, thin edged, the tip rather pointed. 
Vol. V. 18 
