Fertile Bird Hybrids 



Collared Dove ( T. risorius] and these have bred 

 again when paired with the red species. O. 

 tranquebarica, although presenting a general 

 similarity to the collared dove, is truly distinct, 

 being much smaller, with a shorter tail, and dis- 

 playing a marked sex-difference (the male only 

 being red, and the female drab). Its voice is 

 also utterly unlike the well-known penetrating 

 and musical coo of the Collared Dove. 



There is a large class of fertile wild hybrids 

 produced between forms differing only in colour, 

 such as those between the Hooded Crow (Corvus 

 comix) and Carrion Crow (Corvus corone), the 

 various species of Molpastes bulbuls, and the 

 Indian Roller (Coracias indica) and Burmese 

 Roller (C. affinis). Indeed, it may be said that 

 wherever two such colour-species meet they 

 hybridize and become more or less fused. 



In this connection sportsmen, as mentioned 

 by Darwin, performed unconsciously a most in- 

 teresting experiment when, more than a century 

 ago, they introduced largely into their coverts 

 the Chinese Ring-necked Pheasant (Phasianus 

 torquatus] and the J apanese P. versicolor. So freely 

 has the former bred with the common species 

 already present there (Phasianus colchicus) that 

 nowadays nearly all our English pheasants show 

 traces of the cross in the shape of white feathers 

 on the neck, or the green tinge of the plumage of 

 the lower back. The influence of the Japanese 



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