The Making of Species 



grandparents of Linus I. had exceptionally long 

 hair. 



Coming now to birds we find several undoubted 

 examples of mutations, or new forms which have 

 come suddenly into being. 



The black-winged peafowl, whose peculiarities 

 were commented on by Darwin, afford a striking 

 example of this phenomenon. These birds breed 

 true when mated together, and are known to 

 have arisen from common peafowl in no less 

 than nine instances. The cocks have the wings 

 (except the primary quills), black glossed with 

 blue and green, and have the thighs black, 

 whereas, in the ordinary peacock, the same part 

 of the wing is nearly all mottled black and pale 

 buff, and the thighs are drab. The black-winged 

 hen, on the other hand, is nearly white, but has 

 a black tail and black speckling on the upper 

 surface of the body, while her primary quills are 

 cinnamon coloured as in male peafowl, not 

 drab as in the normal hens. The young are 

 white when hatched, the young cock gradually 

 assuming the dark colour as he matures. 



This mutation, which, in one case quoted by 

 Darwin, increased among a flock of peafowl 

 until the black-winged supplanted the ordinary 

 kind, is so distinct in appearance in all stages 

 that it was formerly supposed to be a true species 

 (Pavo nigripennis), of which the wild habitat was 

 unknown. 



