Chap. XIII.] INSTRUMENTAL MUSIC. 59 



vibratory movement apparently serves merely to" make a 

 noise, for it can hardly add to the beauty of their plu- 

 mage. Turkey-cocks scrape their wings against the 

 ground, and some kinds of grouse thus produce a buzzing 

 sound. Another North American grouse, the Tetrao um- 

 helhcs^ when with his tail erect, his ruffs displayed, " he 

 shows off his finery to the females, who lie hid in the 

 neighborhood," drums rapidly with his " lowered wings 

 on the trunk of a fallen tree," or, according to Audubon, 

 against his own body ; the sound thus produced is com- 

 pared by some to distant thunder, and by others to the 

 quick roll of a drum. The female never drums, " but flies 

 directly to the place where the male is thus engaged." In 

 the Himalayas the male of the Kalij-pheasant " often makes 

 a singular drumming noise with his wings, not unlike the 

 sound produced by shaking a stiff piece of cloth." On the 

 west coast of Africa the little black-weavers (Ploccus ?) 

 congregate in a small party on the bushes round a small 

 open space, and sing and glide through the air with 

 quivering wings, "which make a rapid whirring sound 

 like a child's rattle." One bird after another thus per- 

 forms for hours together, but only during the couiting- 

 season. At this same season the males of certain night- 

 jars (Caprimiilgus) make a most strange noise with their 

 wings. The various sj^ecies of woodpeckers strike a 

 sonorous branch with their beaks, with so rapid a vibrato- 

 ry movement that " the head appears to be in two places 

 at once." The sound thus prodixced is audible at a con- 

 siderable distance, but cannot be described ; and I feel 

 sure that its cause would never be conjectured by any one 

 who heard it for the first timq. As this jarring sound is 

 made chiefly during the breeding-season, it has been con- 

 sidered as a love-song ; but it is perhaps more strictly a 

 love-call. The female, when driven from her nest, has 

 been observed thus to call her mate, who answered in the 



