96 Colour and Other Characters in Pigeons 



In all the blues from Series D, as from Series G, the blue feathers were 

 tinged with rusty brown. 



In all then from ^i of Series D 29 F^ birds were reared, of which 

 12 were white, 6 white and black (white preponderating), 1 white and 

 blue, 5 black and white (black preponderating) and 5 blue and white. 

 From Series (7, 31 i^a birds were produced, 9 white, 11 white and black, 

 7 black and white, 4 blue and white, or adding the two series together, 

 out of a total of 60 F^ young, 21 white, 17 white and black, 1 white 

 and blue, 12 black and white, 9 blue and white. 



There are several points connected with these results which call for 

 comment. First, the factor for blue is evidently introduced by the 

 whites, but being recessive to black does not appear in F^. In F.^. almost 

 exactly one-fourth of the coloured young are blue (9 out of 38). My 

 results in this respect confirm those of Staples-Browne^ obtained with 

 other breeds. It is interesting that the blue of the wild rock pigeon 

 should be recessive (hypostatic) to the more recently acquired black 

 of the domestic breeds. 



Another point is the absence of extracted blacks. No fully black 

 bird was produced in F^, and only one with as few as 6 white feathers. 

 The fact that the original blacks when paired together gave a black 

 with some (4) white feathers may indicate that pure blackness is not 

 a stable character. A third point is the excess of whites over expecta- 

 tion (21 out of 60 where 15 would be expected). This is not a great 

 difference in itself, but a similar excess was found in Series B above 

 (10 out of 27), and again in some of the matings described below. 



It has been seen that ^i birds with more white than black in the 

 plumage when paired together give among their coloured offspring not 

 only young like themselves, but also blacks with a relatively small 

 amount of white. With the object of discovering whether this difference 

 corresponds with a difference of constitution several pairings between 

 such 'black with white' birds were made. Since birds of the same 

 generation were not available, F^ birds were crossed with F^ which were 

 nearly similar in distribution of colour. In the first of these crosses 

 {G Ga II) an F^ from G, black, with nearly white rump and a few scattered 

 white feathers, was crossed with an F^ from Ga I, black with only six 

 white feathers. Four young were produced, one black with white, two 

 wholly black, and one blue with no white feather. In this case 

 therefore there were three self-coloured to one black with a few white 

 feathers. But in a second pairing of the same kind (GGalll) of 



1 Proc. Zool. Soc. 1908. 



