94 SEXUAL SELECTION : BIEDS. Part IL 



together, but it appears that when sexual selection 

 has been highly influential, and has given bright 

 colours to the males of any species, it has also very 

 often given a strong tendency to pngnacity. We 

 shall meet with nearly analogous cases when we treat 

 of mammals. On the other hand, with birds the power 

 of song and brilliant colours have rarely been both 

 acquired by the males of the same species ; but in this 

 case, the advantage gained would have been identically 

 the same, namely success in charming the female. 

 Nevertheless it must be owned that the males of several 

 brilliantly-coloured birds have had their feathers spe- 

 cially modified for the sake of producing instrumental 

 music, though the beauty of this cannot be compared, 

 at least according to our taste, with that of the vocal 

 music of many songsters. 



We will now turn to male birds which are not 

 ornamented in any very high degree, but which 

 nevertheless display, during their courtshij^, whatever 

 attractions they may possess. These cases are in some 

 respects more curious than the foregoing, and have been 

 but little noticed. I owe the following facts, selected 

 from a large body of valuable notes, sent to me by Mr. 

 Jenner Weir, who has long kept birds of many kinds, in- 

 cludinof all the British Frino^illidse and Emberizidae. The 

 bullfinoh makes his advances in front of the female, 

 and then puffs out his breast, so that many more of the 

 crimson feathers are seen at once than otherwise would 

 be the case. At the same time he twists and bows his 

 black tail from side to side in a ludicrous manner. The 

 male chaffincli also stands in front of the female, thus 

 shewing his red breast, and "blue bell," as the fanciers 

 call his head ; the wings at the same time being slightly 

 expanded, with the pure white bands on the shoulders 

 thus rendered conspicuous. The common linnet distends 



