I 54 TETRAONID^E : GROUSE. 



beats the air. Those who are interested to follow up 

 the subject may refer to Dr. Coues' Birds of the North- 

 west, where the views of many writers are collated and 

 compared, the author coming to the conclusion that the 

 last explanation here given is the correct one. No one 

 who has heard the whirring of the tiny Humming-bird, 

 or the " booming " of the night-hawk, and witnessed the 

 extraordinary aerial antics of the latter bird at the 

 moment the sound is produced, can doubt that the rapid 

 movement of feathers in the air may make so much 

 noise that there is no difficulty in explaining the rum- 

 bling sounds that come from the Ruffed Grouse in the 

 same way, contrary as it is to the familiar clapping of 

 the wings of the barn-yard fowl. The bird's " music " 

 would, therefore, appear to be literally that of a wind 

 instrument unlike the vocalization of most Grouse, 

 and also different from the playing upon a stringed in- 

 strument which results in the stridulation of many in- 

 sects, which literally fiddle upon themselves by scraping 

 together different parts of the body. As to the reason 

 why the Grouse indulges in such performances, it may 

 be said that it is primarily a manifestation of sexual 

 vigor and desire, universally admired by the fair of the 

 opposite sex, like all other masculine demonstrations, 

 from the most delicately suggestive to the most effec- 

 tually operative. But the Grouse drums both in and 

 out of love ; so that it seems to be done often for his 

 own amusement, or to work off his animal spirits. The 

 excessive muscular motility induced when the bird has 

 his spasms may be imagined when we reflect that the 

 great stiff wings move up and down too rapidly to be 

 perceived by the human eye, and that millions of cubic 

 yards of air are set in vibration audible to our dull ears. 



