34 THE EVOLUTION THEORY 



Bat the most conclusive proof of descent from a single wild 

 species is afforded by the pigeons, and as the production of new 

 breeds amoug them has been, and will continue to be, carried on with 

 particular enthusiasm and deliberateness, I propose to deal with them 

 somewhat more in detail. 



Darwin's work proves beyond a doubt that all our present-day 

 breeds of pigeons are descended from a single wild species, the rock- 

 dove, Columba livia. In appearance, this form, which still lives in 

 a wild state, differs little from our half-wild blue-grey field-pigeon. 

 It has the same metallic shimmer on the feathers of the neck, the 

 same two black cross-bars on the wings as well as the band over the 

 tail, and it has also the same slate-blue general colour. Now, all 

 breeds of pigeons are without restriction fertile inter se, so that any 

 breed can be crossed with any other, and it often happens that, in 

 the products of such crossing, characters appear which the parents, 

 that is, the two or more crossed breeds, did not possess, but which 

 are among the characters of the rock-dove. Thus Darwin obtained, 

 lyv crossing a pure white fan tail with a black barb, hybrids which 

 were partly blackish brown, partly mixed with white, but when he 

 crossed these hybrids with others from two breeds which were 

 likewise not blue, and had no bars, he obtained a slate-blue rock- 

 pigeon, with bars on the wings and tail. We shall inquire later on 

 how far it is correct to regard such cases as reversions to remote 

 ancestors, but if we take it for granted in the meantime, we have 

 here a proof of the descent of our breeds from a single wild species. 

 This is corroborated, too, by everything that we know about the 

 distribution of the rock-pigeon and the place and time of its 

 domestication. It still lives on the cliff-guarded shores of England, 

 Brittany, Portugal, and Spain, and both in India and in Egypt there 

 were tame pigeons at a very early period. Pigeons appear on the 

 menu of a Pharaoh of the fourth dynasty (3000 b. a), and of India 

 we know at least that in 1600 a.d. there were 20,000 pigeons 

 belonging to the court of one of the princes. 



The beauty of this bird, and the ease with which it can be tamed, 

 obviously called man's attention to it at a very early date, and it has 

 been one of man's domestic companions for several thousands of years. 

 Now we can distinguish at least twent}^ main races (Fig. 1), which 

 differ from each other as markedly as, if not more markedly than, the 

 most nearly allied of the 288 wild species of pigeons which inhabit 

 the earth. We have carriers and tumblers, runts and barbs, pouters, 

 turbits and Jacobins, trumpeters and laughers, fantails, swallows, 

 Indian pigeons, &c. 



