154 Birds of Colorado 
white tips; breast covered with scaly, stiff, worn feather-bases from 
which project black, hair-like filaments; a patch of downy white 
feathers on either side of the neck cover the naked tympanum or air 
sac, which is enormously inflated under sexual excitement ; flanks and 
leg feathers mottled likethe back. Billblack; air-sacsyellow. Length 
30-0; wing 13-0; tail 12-0; culmen 1-5; tarsus 2-25; weight up to 
941bs. (Morrison). 
Before the breeding season the breast of the male is black. The 
female is much smaller than, the male—length about 20, wing 11-0; the 
throat and breast are mottled like the back, but with more white, the 
air-sac is present but quite small, and there are no specially modified 
feathers. 
Distribution.—The sage-brush plains of western North America from 
south British Columbia and North Dakota, south to south-east 
California and New Mexico. A resident with a slight vertical migra- 
tion in some parts. 
In Colorado the Sage-Hen is a resident chiefly in the drier sage-brush 
plains of the north and west of the State, but goes up to a certain 
extent into the mountains and breeds as high as 9,000 feet at Dillon 
(Carter)* and near Twin Lakes (Henshaw & Scott); but it does not 
seem, to occur at allin the eastern plains. The following are localities : 
Grand, Routt and Gunnison cos. (Warren), Mesa co. (Rockwell), near 
Cortez (Morrison), the lower Trinchera Valley in Costilla co. (Brunner 
in litt.). 
Habits——The Sage-Grouse or Sage-Hen is the largest 
American game-bird except the Turkey, and is remark- 
able in many respects. It is almost entirely confined 
to the sage-brush (Artemesia) areas, and its diet is largely 
confined to the shoots and leaves of these desert plants, 
and as a result—unless drawn immediately after it is 
killed—its flesh is far from palatable. 
The mating season begins early, and the courting 
habits are very remarkable. The males strut round 
with the yellow air-sacs enormously distended, so that the 
whole head and neck are balloon-like in appearance. 
With tail standing erect they scrape their breasts 
along the bare ground and finish the performance by 
expelling the air from the sacs with a chuckling, rumbling 
*It was probably in this neighbourhood that it was seen by Fremont, June 
20th, 1844. 
