42 GEOtrSE AND WILD TXJEKEYS OF UNITED STATES. 



The dusky grouse cock is quite uniformly dark in color, as the 

 name implies. In the mating season the bird presents a striking 

 appearance; The brilliant comblike wattles above its eyes are con- 

 spicuous, the large, yellow wind sacs on the sides of its neck are fully 

 inflated, and it struts about like a turkey cock, with drooping wings 

 and spreading tail, emitting a sound that closely resembles the hoot- 

 ing of the great horned owl. The nesting takes place during the last 

 half of May, when the hen bird scratches a slight hollow in the earth 

 and lays from 6 to 12 cream-colored, brown-spotted eggs. Usually 

 but one brood is reared in a season. Prof. W. W. Cooke, in writing of 

 the habits of the species in Colorado, says that it breeds from 7,000 

 feet altitude to timber line, 4,000 feet higher. At the former altitude- 

 it lays about the middle of May. In August the birds gather in 

 flocks and visit gra infields, or frequent the more open gulches and 

 foothills for berries. In September they wander above timber line 

 to feed on grasshoppers, reaching an altitude of 12,500 feet. In 

 severe winter weather some of the birds come down into the thick ^ 

 woods, but many remain the whole year close to timber line." 



FOOD HABITS. 



The food .habits of the dusky grouse have been studied by examina- 

 tion of the contents of 45 crops and stomachs, representing every 

 month of the year except May, June, and November. Most of the 

 birds were shot in British Columbia, Colorado, and Idaho, but a few 

 came from Montana, Utah, Wyoming, and California. The food 

 consisted of 6.73 percent anim.^l matter — insects, with an occasional 

 spider — and 93.27 percent of vegetable matter — seeds, fruit, and 

 leaves. Grasshoppers constitute tha bulk of the animal food, amount- 

 ing to 5.73 percent. Beetles, ants, tnd caterpillars form the rest of 

 the insect food. One stomach contained the common land snail 

 {Polygyra sp.). Major Bendire, Vernon Bailey, and Walter K. 

 Fisher have shown that the young birds feed largely on grasaboppers. 

 Mr. Fisher shot a young bird at Forest Grove, Oreg., Julj 6, 1897, 

 which had eaten 20 grasshoppers and several smooth, green larvse. 



Vegetable Food. 



The dusky grouse and its near relative, the spruce grouse, are 

 among our chief foliage-eating birds. Browse is eaten by the blue 

 grouse to the extent of 68.19 percent of its annual food, and is dis- 

 tributed as follows : Buda and twigs, 5.28 percent ; coniferous foliage, 

 54.02 percent ; other leaves, 8.89 percent. The species spends most of 



"Birds of Colorado, p. 70, 1897. 



