THE RED GROUSE PTARMIGAN. 171 
entire length is about sixteen inches, the weight 
about one and a half pounds. 
According to Dr Richardson, the Willow Grouse 
is partially migratory in the fur countries ; it breeds 
in the valleys of the Rocky Mountains, and, collecting 
in flocks on the approach of winter, retires south- 
ward as the severity of the weather increases. On 
the shores of Hudson’s Bay, it assembles in vast flocks 
during winter, 10,000 being sometimes captured in 
a single season. Greenland, Iceland, and the valleys 
of the Alps, are almost their only habitations in the 
old world, frequenting rather wet and brushy situa- 
tions. In America, they shelter themselves among 
the thickets of willow and dwarf birch. They pass 
the night in holes in the snow, and when perceived, 
practise a novel artifice in attempting to escape ; they 
often terminate their flight by diving precipitately in- 
to the loose snow, working their way with considerable 
celerity beneath its surface. 
The next bird we shall notice is 
