Chap. VI. THEIR REVERSION IN COLOUR. 201 



by Mr. Wicking, who has had more experience than any 

 other person in England in breeding pigeons of various 

 colours: namely, that when a blue, or a blue and che- 

 quered bird, having black wing-bars, once appears in any 

 race and is allowed to breed, these characters are so strongly 

 transmitted that it is extremely difficult to eradicate them. 



What, then, are we to conclude from this tendency in all 

 the chief domestic races, both when purely bred and more 

 especially when intercrossed, to produce offspring of a blue 

 colour, with the same characteristic marks, varying in the same 

 manner, as in Columba livia ? If we admit that these races 

 have all descended from C. livia, no breeder will doubt that 

 the occasional appearance of blue birds thus characterised 

 is accounted for on the well-known principle of " throwing 

 back" or reversion. Why crossing should give so strong a 

 tendency to reversion, we do not with certainty know ; but 

 abundant evidence of this fact will be given in the following 

 chapters. It is probable that I might have bred even for a 

 century pure black barbs, spots, nuns, white fantails, trumpeters, 

 &c, without obtaining a single blue or barred bird; yet by 

 crossing these breeds I reared in the first and second genera- 

 tion, during the course of only three or four years, a consider- 

 able number of young birds, more or less plainly coloured blue, 

 and with most of the characteristic marks. When black and 

 white, or black and red birds, are crossed, it would appear that 

 a slight tendency exists in both parents to produce blue off- 

 spring, and that this, when combined, overpowers the separate 

 tendency in either parent to produce black, or white, or red 

 offspring. 



If we reject the belief that all the races of the pigeon are 

 the modified descendants of C. livia, and suppose that they 

 are descended from several aboriginal stocks, then we must 

 choose between the three following assumptions: firstly, that 

 at least eight or nine species formerly existed which were 

 aboriginally coloured in various ways, but have since varied 

 .in so exactly the same manner as to assume the colouring 

 ■of (7. livia; but this assumption throws not the least light on 

 the appearance of such colours and marks when the races are 

 crossed. Or secondly, we may assume that the aboriginal species 



