PTARMIGAN 
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derings. Such local migrations also serve to mix 
the blood of the different stocks, and so to 
strengthen the breed on all the moors alike. 
PTARMIGAN. 
{Lagopus mutus.) 
White Grouse, Rock Grouse. — The Ptarmigan 
is a bird of the bare, rocky mountain-tops, above 
the limit of tree growth, and in this country is only 
found on some of the highest mountains in Scot- 
land. It has the habit, common to most birds 
and animals of Arctic climates, of gaining an 
almost completely white plumage in winter-time. 
In size it is a little smaller than the Grouse, and 
its finely mottled, greyish-brown summer plumage 
is as perfectly adapted to concealing it among the 
bare stones and dwarf and scanty plants which 
clothe the mountain-tops at that time as its dress 
of snowy whiteness is in winter. By far the 
greater number of the " Ptarmigan " of the game- 
shops are Continental Willow Grouse in winter 
plumage ; the true Ptarmigan is distinctly smaller 
in size, and the cock has also a black stripe across 
the eye. In both species alike there is a black 
patch beneath the tail. Towards the end of May 
the Ptarmigan scrapes a hollow in the ground, and 
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