Chap. XIII. INSTRUMENTAL MUSIC. 61 



from a distance to a male under confinement; but as 

 the black-cock continues his spe? for hours during 

 successive days, and in the case of the capercailzie 

 *• with an agony of passion," we are led to suppose 

 that tlie females whicli are already present are thus 

 charmed.''^ The voice of the common rook is known 

 to alter during the breeding-season, and is therefore in 

 some way sexual.^^ But what shall we say about the 

 harsh screams of, for instance, some kinds of macaws ; 

 have these birds as bad taste for musical sounds as 

 they apparently have for colour, judging by the in- 

 liarmonious contrast of their bright yellow and blue 

 plumage ? It is indeed possible that the loud voices 

 of many male birds may be the result, without any 

 advantage being thus gained, of the inherited effects of 

 the continued use of their vocal organs, when they are 

 excited by the strong passions of love, jealousy, and 

 rage ; but to this point we shall recur when we treat of 

 quadrupeds. 



We have as yet spoken only of the voice, but the 

 males of various birds practise, during their courtship, 

 what may be called instrumental music. Peacocks 

 and Birds of Paradise rattle their quills together, 

 and the vibratory movement apparently serves merely 

 to make a noise, for it can hardly add to the beauty 

 of their plumage. Turkey-cocks scrape their wings 

 against the ground, and some kinds of grouse thus 

 produce a buzzing sound. Another North American 

 grouse, the Tetrao umbellus, when with his tail erect, 

 his ruffs displayed, *' he shows off his finery to the 

 " females, who lie hid in the neighbourhood," drums 

 rapidly wdth his " lowered wings on the trunk of ix^ — 



-^ ^^' 



« L. Lloyd, ' The Game Birds of Sweden,' &c., 1867, p. 22, SkS^' q 



^0 Jenner, ' Philosoph. Trausactious,' 1824, p. 20. /c;^ O^ 



