R. Staples-Browne 137 



specimens. On breeding them together, however, certain varieties were 

 obtained, and, as will be seen, they were obviously heterozygous in at 

 least two characters. It frequently happens that semi-domesticated 

 birds join the Rock Doves in their breeding haunts, and no doubt often 

 ci-oss with them. It is stated in Yarrell's British Birds, 4th edition. 

 Vol. Ill, p. 14, that " even in Yorkshire and Northumberland the birds 

 found are open to the suspicion of not being pure wild birds." In 1906 

 I visited several caves near Flamborough Head which were frequented 

 by these birds in large numbers, and, although no varieties were seen 

 on the day of my visit, I was informed by the boatmen that lighter and 

 darker birds and whites were frequently seen and shot there. 



Test experiments with Lincolnshire Rock Doves. 



When the Lincolnshire Rock Doves were bred together a mixed 

 generation, consisting of three distinct types, was produced. To 

 determine the relationship of these types to one another matings in 

 the direct line were continued and two more generations were raised. 

 The details of the experiments are given in Series A (Exps. 47 — 49), 

 and the results tabulated in Table I. 



Types of birds produced from the Lincolnshire Rock Doves. 



(1) Typical G. livia. These birds were identical in every respect 

 with their parents. This type behaves as a dominant to the other two 

 types produced. One of these birds, mated to white, forms a starting 

 point of some of the experiments described in Series B {v. Exp. 52). 



(2) Blue riimped Rock Dove. The plumage of this type resembled 

 that of the sub-species of Rock Dove known as C. intermedia. The 

 colour of the rump was slightly lighter than that of the back. On 

 examining the series of skins of C. intermedia in the British Museum 

 I noticed that specimens varied slightly in the colour of the rump, some 

 being darker than others. Mr Blyth informed Darwin that the rumps 

 of C. intermedia were sometimes albescent {Animals and Plants under 

 domestication, 2nd edition, Vol. I, p. 193). In the whole of these 

 experiments thirty birds of this type have been produced, and although 

 the colour of the rump varied slightly, the character was always quite 

 distinct, and could be seen at a very early age. In the following 

 descriptions this type is alluded to as Blue with no white feathers 

 (Bl. no wh.). 



10—2 



