240 THE STORY OF THE BIRDS 



of Sexual Selection, and from a cursory review 

 of the facts this seems to be a very plausible and 

 possible explanation of the phenomenon. The 

 subject, however, has been much more minutely 

 investigated since Darwin worked and wrote, 

 and a vast array of facts has been collected 

 which not only tend to weaken his brilliant 

 hypothesis, but alsolutely to refute it. The 

 keystone of Darwin's arch was the taste or 

 choice of the female bird for certain charac- 

 teristics either ornate, musical, or terpsichorean, 

 in the male. But Taste or Choice is one of the 

 least constant things in this world. Darwin's 

 theory demands the practically impossible co- 

 incidence of choice throughout entire species 

 and groups of species, which, we venture to 

 assert, is demanding far too much from the 

 female members of them. All the evidence 

 tends to show that this song and display are 

 prompted by impulses of pleasure or rage, and 

 that spontaneous vitality which is invariably 

 attendant upon robust health. The impulse to 

 pair becomes strongest when life is in the full 

 tide of its vigour, seasonably after maturity ; 

 and these are the periods when ornaments are 

 brightest, when songs are gladdest, and when 

 display of all kinds is most vigorous. Male 



