Chap. VIII. EXTEKNAL DIFFERENCES. 279 



occurred in Sweden, Mr. Hewitt found that his young birds 

 always changed and deteriorated in character in the course 

 of two or three generations ; notwithstanding that great care 

 was taken to prevent any crossing with tame ducks. After 

 the third generation his birds lost the elegant carriage of the 

 wild species, and began to acquire the gait of the common 

 duck. They increased in size in each generation, and their 

 legs became less fine. The white collar round the neck of the 

 mallard became broader and less regular, and some of the longer 

 primary wing-feathers became more or less white. When this 

 occurred, Mr. Hewitt almost destroyed his old stock and procured 

 fresh eggs from wild nests ; so that he never bred the same 

 family for more than five or six generations. His birds continued 

 to pair together, and never became polygamous like the common 

 domestic duck. I have given these details, because no other 

 case, as far as I know, has been so carefully recorded by a 

 competent observer of the progress of change in wild birds 

 reared for several generations in a domestic condition. 



From these considerations there can hardly be a doubt that 

 the wild duck is the parent of the common domestic kind ; nor 

 need we look to distinct species for the parentage of the more 

 distinct breeds, namely, Penguin, Call, Hook-billed, Tufted, and 

 Labrador ducks. I will not repeat the arguments used in the 

 previous chapters on the improbability of man having in ancient 

 times domesticated several species since become unknown or 

 extinct, though ducks are not readily exterminated in the wild 

 state; — on some of the supposed parent-species having had 

 abnormal characters in comparison with all the other species of 

 the genus, as with hook-billed and penguin ducks ; — on all the 

 breeds, as far as is known, being fertile together "; 10 — on all 

 the breeds having the same general disposition, instinct, &c. 

 But one fact bearing on this question may be noticed : in the 

 great duck family, one species alone, namely, the male of 



10 I have met with several statements quite fertile, though they were not bred 



on the fertility of the several breeds when inter se, so that the experiment was not 



crossed. Mr. Yarrell assured me that fully tried. Some half-bred Penguins 



Call and common ducks are perfectly and Labradors were again crossed with 



fertile together. I crossed Hook-billed Penguins, and subsequently bred by 



and common ducks, and a Penguin and me inter se, and they were extremely 



Labrador, and the crossed ducks were fertile. 



