64 GLIMPSES OF INDIAN BIRDS 



the more beautiful. It is my belief that at one time 

 both sexes of both species of Indian robin were coloured 

 as the hens now are. Later, a mutation arose in the 

 cock whereby all his plumage save the back became 

 black, and when this mutation became fixed in the 

 species, the cock had advanced a stage in his evolution- 

 ary progress. A still more advanced stage was reached 

 when the whole of the plumage became black. Could 

 we peep a thousand years into the future, it is quite 

 likely that we should find that the northern species of 

 Indian robin had acquired a black back. 



Some may think that these statements are far- 

 fetched. I submit that they are nothing of the kind. 

 Not infrequently it happens that hen birds develop 

 the plumage of the male. Again, sometimes of two 

 closely allied species one displays marked sexual 

 differences, while the sexes of the other are difficult 

 to distinguish. Every one is familiar with the showy 

 drake and the dull-coloured hen of the common 

 mallard or wild duck of Europe (Anas boscas), and 

 we in India are equally familiar with an allied species 

 the spotted bill (A. poecilorhyncha) , in which both 

 sexes are dull-coloured like the female mallard. 

 The cock mallard is a stage ahead of the hen mallard 

 and of both sexes of the spotted bill as regards evo- 

 lutionary development. A thousand years hence 

 the male spotted-bill may have developed a coat 

 of many colours. The foregoing will not be acceptable 

 to the old-fashioned Darwinians, but as these 

 cannot explain satisfactorily how it is that natural 

 selection has given cock robin in Northern India 



