X COLOURS AND ORNAMENTS CHARACTERISTIC OF SEX 285 



descend rapidly from a great height. All these are probably 

 recognition and call notes, useful to each species in relation 

 to the most important function of their lives, and thus capable 

 of being developed by the agency of natural selection. 



Decorative Plumage of Birds and its Display. 



Mr. Darwin has devoted four chapters of his Descent of 

 Man to the colours of birds, their decorative plumage, and 

 its display at the pairing season ; and it is on this latter 

 circumstance that he founds his theory, that both the 

 plumage and the colours have been developed by the prefer- 

 ence of the females, the more ornamented males becoming the 

 parents of each successive generation. Any one who reads 

 these most interesting chapters will admit, that the fact of the 

 display is demonstrated ; and it may also be admitted, as highly 

 probable, that the female is pleased or excited by the display. 

 But it by no means follows that slight differences in the shape, 

 pattern, or colours of the ornamental plumes are what lead a 

 female to give the preference to one male over another ; still 

 less that all the females of a species, or the great majority of 

 them, over a wide area of country, and for many successive 

 generations, prefer exactly the same modification of the colour 

 or ornament. 



The evidence on this matter is very scanty, and in most 

 cases not at all to the point. Some peahens preferred an old 

 pied peacock ; albino birds in a state of nature have never 

 been seen paired with other l)irds ; a Canada goose paired Avith 

 a Bernicle gander ; a male widgeon preferred a pintail duck 

 to its own species ; a hen canary preferred a male greenfinch 

 to either linnet, goldfinch, siskin, or chaffinch. These cases 

 are evidently exceptional, and are not such as generally occur 

 in nature ; and they only prove that the female does exert 

 some choice between very different males, and some observa- 

 tions on birds in a state of nature prove the same thing ; but 

 there is no evidence that slight variations in the colour or 

 plumes, in the way of increased intensity or complexity, are 

 what determines the choice. On the other hand, Mr. Darwin 

 gives much evidence that it is not so determined. He tells us 

 that Messrs. Hewitt, Tegetmeier, and Brent, three of the 

 highest authorities and best observers, " do not believe that 



