INSTINCTS OF MOLOTHRUS 



of the genus. Moreover, just as a criminal will practise 

 upon his own class, just as there is no honour among 

 thieves, but thief will rob thief, so one species of Molo- 

 thrus, viz., M. rufo-axillaris, will lay its eggs in the 

 nest of M. badius, a form which is not itself parasitic. 

 Nature has aided and abetted this iniquitous mode of 

 life in many and varied ways. These have been care- 

 fully studied upon the spot by Mr. W. H. Hudson, from 

 whose account of the same in the Proceedings of the 

 Zoological Society we shall quote. The cow bird appears 

 to have adopted the habits of the cuckoo at a later 

 period in the history of its race than that bird, for it 

 often makes rather serious mistakes. For example, 

 Molothrus has been known to drop its eggs on the 

 ground, omitting to remove them carefully and subse- 

 quently in its bill to some adjacent nest, as does the 

 cuckoo. Its instincts are as yet so primitive and 

 uncultured that the bird will lay its eggs in an old 

 and deserted nest, or fail to hit the right time for egg 

 laying, when its young, being born too late, perish of 

 neglect at the hands of their foster parents. This latter 

 error, however, appears to be remedied by the fact 

 that the young are hatched especially early, and are 

 also peculiarly strong. Molothrus, when it does success- 

 fully lay its eggs in a stranger's nest, is apt to make 

 assurance doubly sure by pecking at and destroying 

 the legitimate eggy occupants of the nest ; in doing 

 this, it will occasionally peck at its own eggs, or rather 

 those of another Molothrus who has been beforehand 

 with it. This danger to future generations of Molothri 

 is to some extent evaded by the very hard nature of the 

 shell, which resists pecking more efficiently than do the 

 eggs of the unconsulted hosts. The cuckoo's eggs, as a 

 matter of quite common knowledge, are varied in hue, 

 so as to give them a better chance of escaping unnoticed 

 in the nests of their unwilling hosts. Precisely the 



158 



