THE RUFFED GROUSE 17 
The species is not strictly migratory, though 
in the northern parts of its range it moves 
southward at times with the severest weather, 
and may change its haunts at any time from 
natural causes, so that a locality may be very 
sparsely populated with grouse at one season 
only to swarm with them the next. 
In the different portions of their range these 
birds vary in their coloring, the bird of Oregon 
and neighboring States being in the most highly 
developed specimens a deep chestnut with warm 
reddish shades in his plumage, and the barrings 
on the flanks and under parts much heavier 
than in the typical bird. This variety is Bon- 
asa umbellus sabinvi in the scientists’ list. The 
Rocky Mountains have another variety, whose 
range is from Alaska, in the Yukon valley, 
southward to Colorado; a race of paler coloring 
and somewhat smaller size. The body color is 
made up of grayish tones and has very little of 
chestnut or reddish shades in the markings. 
From its color scheme this is often called the 
Gray Ruffed Grouse, Bonasa umbellus umbel- 
loides. In the intermediate districts they grade 
imperceptibly one into the other. In the grouse 
of Maine we find a wide variation in color. 
