360 071 Changes of Plumage in Typical Weaver-birds. 



of my large aviaries, where tliey have regularly come into 

 plumage year after year, without any change worth recording, 

 until the early summer of 1896, when one of my males of 

 Q. quelea appeared in the breeding-plumage of Q. russi*. I 

 wrote to Mr. Abrahams respecting this unexpected meta- 

 morphosis, asking whether he had ever noticed a parallel 

 case, and he replied saying that he would take an early 

 opportunity of talking the matter over with me. He evidently 

 imagined that I must have been mistaken. 



It will be seen, on reference to my ' Foreign Finches in 

 Captivity,'' that, writing in 1895, 1 speak of a male of 

 Q. russi quarrelling with cocks of Q. quelea (vide p. 316), 

 and from that time to the present I have added no Weavers 

 to that aviary. There can therefore be no possibility of my 

 having made a mistake. 



"When the two " species " are compared, it will be seen that 

 the chief difference between them consists in the colouring 

 of the mask on the face, which is black in Q, quelea and 

 huffish in Q. russi. The two forms come mixed together in 

 the same consignments from Africa, and doubtless are caught 

 together. It would therefore seem that Q. russi is a mere 

 partial albinism, due to weakening of the pigment-cells. 



In the autumn of 1895 I purchased a number of examples 

 of Pyromelana out of colour, some of which, however, were 

 showing the first indications of change of plumage ; among 

 them were five males of P. franciscana and six of P. afra. 

 All these birds continued to develop their nuptial plumage 

 up to the first frosts, when the change was arrested and the 

 bright colouring gradually receded from the feathers, so that 

 in about six weeks the birds had all resumed their winter 

 plumage. 



Several views have been put forward to account for the 

 change of plumage in birds ; but when the colouring gradually 

 comes and again recedes from the same feathers, the 



* This bird died during its chfiiige into summer plumage, in April 

 of the present year ; it had already acquired for the second time the 

 characteristics of Russ's Weaver. In Quelea this change is effected by 

 a complete moult. 



