248 The World-Evidence. 



the nest in which an egg has been deposited — at any 

 rate, for some time. 



" In all cases where I have found this egg, I have 

 observed both male and female cow-bird lingering 

 near." * 



Major Bendire says positively that : 



" When the young cow-bird is able to shift for him- 

 self, he leaves his foster-parents and joins his own 

 kind." 



VII. The common cat-bird, we are told, rejects 

 and ejects the Molotliriis's egg. f And so do several 

 other birds ; building it over in some cases, when 

 they cannot succeed in ejecting it. 



VIII. Among all the varieties of Molotlirus there 

 is only one which preserves any semblance of true 

 pairing. All the rest are like our cuckoos, and, as 

 Professor Baird decisively says : 



" The screaming cow-bird {Molotlirus rufoaxillaris), 

 is the only parasitical species in which there is con- 

 jugal fidelity;" a point on which Major Bendire 

 speaks to exactly the same effect. J 



More and more, therefore, with these facts before 

 us, we are compelled to regard Mr. Darwin's dictum, 

 that migration is the cause of parasitism in the cuckoo 

 as a most salient instance of the vice of generalising 

 from too narrow a basis of particulars. 



IX. Major Bendire holds that Molotlirus boji- 

 arieiisis once possessed the nest-making instinct, 

 and he tells that twice he has seen birds of this 

 species attempting to build nests, but leaving them 



*John Burroughs, Wake Robin, 

 f Birds of N. America, ii, p. 155. 

 ± P. 88. 



