Decorative Plumage 63 



wherein the more brilliantly plumaged males would have 

 possessed advantages over other males which had not 

 these points to recommend them to the notice of the 

 females. But that such an acquisition of brilliant colouring 

 must have taken a long period of time to accomplish, is 

 also evident, and even if the idea of sexual selection be 

 mere theory, some of the facts which one meets with in a 

 daily study of birds are interesting enough to make one 

 hazard a possible explanation as to how such a develop- 

 ment in the decoration of the male may have proceeded, 

 even if it be impossible to give in detail the exact method 

 by which it was accomplished. That the decorative 

 plumage of the male bird is appreciated by himself and is 

 used by him as an attractive presentation to win the favour 

 of the female, must, it seems to me, be taken as an 

 undoubted fact, whether it be the streaming plumes of a 

 Bird of Paradise ; the hundred-eyed wing of an Argus 

 Pheasant ; the coloured, and, to human notions, somewhat 

 ugly, wattles of a Turkey or Domestic Fowl; the feathered 

 shield of a Ruff; or the naked appendage to the head of a 

 Bell-bird. The way in which the male birds show them- 

 selves off to the females is a proof that they believe in the 

 charm of their decorations. That sexual selection has 

 played a great part in the development of brilliant 

 plumage, seems to me a most feasible conclusion, and a 

 reasonable conjecture as to how the evolution of species 

 may have taken place, can even be hazarded. During the 

 process of writing the ' Catalogue of Birds in the British 

 Museum,' which contains a description of all the species of 

 birds known up to the time of writing the volumes, I must 

 have handled nearly half a million of specimens, and in the 

 volumes written by myself I have described the plumages 

 of not less than 5000 different species, and have given 

 references to the books in which they are mentioned, with 

 a list of the specimens contained in the National Collection. 



