96 THE DOMESTICATION OF ANIMALS 



grain or to render him good service by destroying grubs and 

 the seeds of weeds. 



Among pigeons, the Rock Dove is distinguished by the 

 fine bluish-grey tints of the upper parts of its body, which 

 shade into a pearl-grey spreading from the under surface 

 to the tail feathers, tipped with leaden grey. The throat 

 glistens with metallic purple and green; but the most strik- 

 ing and distinctive markings are the white rump and two 

 black bars across each wing. The birds are rather less than 



Rock Dove ancestor of Scottish dove-cot "doos." $ nat. size. 



a foot in length, almost a third smaller than the familiar 

 Wood Pigeon. Those who have no opportunity of seeing 

 the true Rock Dove in its native haunts can form an ex- 

 cellent idea of its colouring and characteristics from many 

 of the half-wild pigeons of our larger towns ; for the inter- 

 breeding of domestic pigeons run wild, frequently results 

 in a "throw-back" to the original type. Such blue-grey 

 reversions to the Rock Dove type can be seen any day 

 in the streets of Edinburgh. 



There are many reasons for supposing that successful 



