Chai'. VI. THEIK KE VERS] ON IN COLOUR. 207 



of blue and cliequered birds ; but it will now be seen that 

 when two birds belonging to distinct races are crossed, 

 neither of which have, nor probably have had during many 

 generations, a trace of blue in their plumage, or a trace of 

 wing-bars and the other characteristic marks, they very 

 frequently produce mongrel offspring of a blue colour, some- 

 times checiuered, with black wing-bars, &g. ; or if not of a 

 blue colour, yet with the several characteristic marks more 

 or less plainly developed. I was led to investigate this 

 subject from MM. Boitard and Corbie-'' having asserted that 

 from crosses between certain breeds it is rare to get anj^thing 

 but bisets or dovecot pigeons, which, as we know, are blue 

 birds with the usual characteristic marks. We shall here- 

 after see that this subject possesses, independently of our 

 present object, considerable interest, so that I will give the 

 results of my own trials in full. I selected for expei'iment 

 races which, when pure, very seldom produce birds of a blue 

 colour, or have bars on their wings and tail. 



The Nun is white, with the head, tail, and primary wing- 

 feathers black ; it is a breed which was established as Ions: 

 ago as the year 1600. I crossed a male Nun with a female 

 red common Tumbler, which latter variety generally breeds 

 true. Thus neither parent had a trace of blue in the plumage, 

 or of bars on the wing and tail. I should premise that 

 common Tumblers are rarely blue in England. From the 

 above cross I reared several young : one was red over the 

 whole back, but with the tail as blue as that of the rock- 

 pigeon ; the terminal bar, however, was absent, but the outer 

 feathers were edged with white : a second and third nearly 

 resembled the first, but the tail in both presented a trace of 

 the bar at the end : a fourth was brownish, and the wings 

 ^ showed a trace of the double bar : a fifth was pale blue over 

 the whole breast, back, croup, and tail, but the neck and 

 primary wing-feathers were reddish ; the wings presented 

 two distinct bars of a red colour ; the tail was not barred, but 

 the outer feathers were edged with white. I crossed this 

 last curiously coloured bird with a black mongrel of com- 

 plicated descent, namely, from a black Barb, a Spot, and 

 "' Les Pigeons,' &c., p. 37. 



