The Making of Species 



hens, as, for example, the paradise fly-catcher 

 (Terpsiphone parodist), the showy cock shares 

 the burden of incubation equally with the hen. 



It frequently happens that allied species of 

 birds are found in neighbouring countries. The 

 Indian robins, for example, fall into two species. 

 The brown-backed robin ( Thamnobia cambayensis) 

 occurs north of Bombay, while the black-backed 

 species (T. fulicata) is found south of Bombay. 

 The hens of these two species are almost indis- 

 tinguishable, but the cocks differ, in that one has 

 a brown back, while the other's back is glossy 

 black. The Wallaceian theory of colouration 

 seems quite unable to explain this phenomenon 

 the splitting up of a genus into local species 

 which is continually met with in nature. Equally 

 inimical to the theory of protective colouration is 

 the existence, side by side, of species which 

 obtain their living in much the same manner. 

 On every Indian lake three different species of 

 kingfisher pursue their profession cheek by 

 jowl ; one of these Ceryle rudis is speckled 

 black and white, like a Hamburg fowl ; the 

 second is the kingfisher we know in England ; 

 and the third is the magnificent white-breasted 

 species Halcyon smyrnensis a bright-blue bird 

 with a reddish head and a white wing bar. It is 

 obvious that all three of these diversely plumaged 

 species cannot be protectively coloured. It may 

 perhaps be objected that the piscatorial methods 



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