SIEEBA GROUSE 273 



During the spring and early summer, the males are in the habit of 

 taking solitary positions near the tops of pines or firs, sixty or more feet 

 above the ground, where they stand on horizontal limbs close to the trunk. 

 They hold such positions continuously for hours, one day after another, 

 and send forth at intervals their reverberant booming. With different 

 birds the series of notes comprising this booming consists of from five 

 to seven syllables, six on an average. The quality of the sound can be 

 likened to that produced by beating on a water-logged tub, hoont, hoont, 

 hoonV, hoont' , hoont, hoont, crescendo at the first, diminuendo toward the 

 end of the series. As each note is uttered the tail of the bird is depressed 

 an inch or two — perhaps an index to the effort involved. The separate 

 series of notes in two instances were uttered at intervals of 40, 20, 25, 45, 

 12, 21, and 29 seconds, and again 10, 10, 20, 26, 14, 15, 17, 12, 11, 15, 13, 

 28, 17, and 11 seconds respectively. These two birds had been heard 

 booming for a long time before we began to pay special attention to them ; 

 and they continued long after we finished this record. The ventriloquial 

 quality is discovered when one attempts to locate the producer, a difficult 

 feat as a rule. The observer may succeed in locating the proper tree, but 

 is likely to circle it many times, peering upward with painfully aching 

 neck, and still utterly failing to locate the avian performer amid the foliage 

 high overhead. The notes are commonly supposed to be produced by 

 tb^ bird's inflating and exhausting the glandular air sacs on the sides of 

 the 'neck. These sacs are covered by unfeathered yellow skin, and we think 

 it more likely that they serve only as resonators, being kept continually 

 inflated, while the air actually producing the sound passes to and from 

 the lungs along the regular air passage. It rests with someone gifted 

 with patience for long continued observation to determine exactly how the 

 notes are produced. 



By early July the new broods of grouse are to be looked for in the 

 brush-bordered glades of the forests. Two downy young were noted on 

 the trail to Nevada Falls so early as June 21, 1893 (W. 0. Emerson, 1893, 

 p. 179). When the chicks have been partly reared the males desert their 

 mates, and, forming in flocks of 6 or 8, work higher in the mountains. 

 The females remain with, and continue to care for, their offspring, these 

 family units remaining separate for the time being. Finally, as the summer 

 wanes, they, too, work up into the Hudsonian Zone. Thus, while the 

 Mountail Quail go down-hill in the fall, the grouse go iip-hilL 



A 'stag' flock of 8 Sierra Grouse was encountered by the senior author 

 on Warren Fork of Leevining Creek, September 26, 1915, after a light 

 fall of snow. The birds were in lodgepole pines on a level bench at 10,500 

 feet altitude. They flushed one after another with a startling succession 

 of loud whirs, all taking off in the same general direction and alighting 



