FATE OF THE HALF-CASTE 337 



inhabit in the breeding-season, and thus being 

 brought into contact with aliens. 



The only common wild hybrid is the apparently 

 sterile one between two very distinct species of 

 Grouse, the Capercailzie and Blackcock, which is 

 so well known on the Continent as to have a tech- 

 nical name, Rakkelhane, in Scandinavia. Many 

 examples are to be seen in museums, and the cock 

 hybrid is killed down by sportsmen as vermin, 

 as it disturbs the pure-bred birds at their tourna- 

 ments ; the hens are inconspicuous and seldom 

 noticed. 



As to the common crosses of all grades between 

 such birds as only or hardly differ except in colour, 

 such as the Hooded Carrion-Crow crosses and 

 others above-mentioned, I cannot consider them 

 hybrids at all; as the birds, who ought to know 

 their own nationality best, make no caste- distinc- 

 tions on colour, I cannot see why naturalists should 

 presume to do so. 



Abnormalities in coloration which appear inde- 

 pendently of crossing are often very interesting, 

 whether they occur in tame, captive, or wild birds ; 

 in the last case the frequent whiteness or pied varie- 

 gation of the Blackbird is of ancient notoriety, for 

 Aristotle mentions white Blackbirds (which he 

 thought were of a distinct species), and Varro 

 speaks of their being shown publicly in Rome, along 

 with Parrots, wild Fowls (probably Blackgame) and 

 other curiosities. In the Faroes, a pied variety of 

 the Raven used to occur frequently, but has now be- 



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