212 INSTINCT. Chap. VII. 



the migratory instinct, both in extent and direction, 

 and in its total loss. So it is with the nests of birds, 

 which vary partly in dependence on the situations 

 chosen, and on the nature and temperature of the 

 country inhabited, but often from causes wholly un- 

 known to us : Audubon has given several remarkable 

 cases of differences in nests of the same species in the 

 northern and southern United States. Fear of any 

 particular enemy is certainly an instinctive quality, as 

 may be seen in nestling birds, though it is strengthened 

 by experience, and by the sight of fear of the same 

 enemy in other animals. But fear of man is slowly 

 acquired, as I have elsewhere shown, by various animals 

 inhabiting desert islands ; and we may see an instance 

 of this, even in England, in the greater wildness of 

 all our large birds than of our small birds ; for the 

 large birds have been most persecuted by man. We 

 may safely attribute the greater wildness of our large 

 birds to this cause ; for in uninhabited islands large 

 birds are not more fearful than small ; and the magpie, 

 so wary in England, is tame in Norway, as is the 

 hooded crow in Egypt. 



That the general disposition of individuals of the same 

 species, born in a state of nature, is extremely diversified, 

 can be shown by a multitude of facts. Several cases 

 also, could be given, of occasional and strange habits in 

 certain species, which might, if advantageous to the 

 species, give rise, through natural selection, to quite new 

 instincts. But I am well aware that these general state- 

 ments, without facts given in detail, can produce but a 

 feeble effect on the reader's mind. I can only repeat my 

 assurance, that I do not speak without good evidence. 



The possibility, or even probability, of inherited 

 variations of instinct in a state of nature will be 

 strengthened by briefly considering a few cases under 



