104 Instinct of the Cuckoo. 



example of the European cuckoo. From this 

 fact Darwin undertakes to derive the origin of 

 the unique instinct of the latter by means of nat 

 ural selection. &quot; Suppose,&quot; he says, &quot; that the 

 ancient progenitor of our European cuckoo had 

 the habit of the American cuckoo, and that she 

 occasionally laid an egg in another bird s nest. 

 If the old bird profited by this occasional hab 

 it, through being enabled to migrate earlier or 

 through any other cause ; or if the young were 

 made more vigorous by advantage being taken of 

 the mistaken instinct of another species than 

 when reared by their own mother, encumbered, 

 as she could hardly fail to be, by having eggs 

 and young of different ages at the same time- 

 then the old birds or the fostered young would 

 gain an advantage. And analogy would lead us 

 to believe that the young thus reared would be 

 apt to follow by inheritance the occasional and 

 aberrant habit of their mother, and in their turn 

 would be apt to lay their eggs in other birds 

 nests, and thus be more successful in rearing their 

 young. By a continued process of this nature I 

 believe that the strange instinct of our cuckoo 

 has been generated.&quot; 



This hypothesis raises many interesting ques 

 tions for the scientist, but we are only concerned 



