3O2 Habit and Instinct. 



excluded, the habit has not become congenitally linked 

 with a visual stimulus ; where natural selection is in 

 operation, the habit has become congenitally linked with 

 a touch or taste stimulus. 



Allusion has already been made to the fact that the 

 young jungle pheasants of Assam, when left motherless, 

 die of starvation, if their attention be not attracted to 

 grains of food ; and the same is said to be true of incubated 

 ostriches. Here, too, the normal action of the mother 

 shields the young from the incidence of natural selection. 

 But young megapodes are not fostered by the parent ; 

 they are not shielded from the incidence of natural selection. 

 In these birds we might, on selectionist principles, expect 

 to find a more definitely congenital response to the sight 

 of certain appropriate kinds of food. " I have several 

 times," says Dr. D. C. Worcester, in a letter to me, 

 " observed young megapodes feeding quite by themselves 

 in the woods, and, upon shooting them, have found them 

 to agree perfectly in size and plumage with specimens 

 caught in the mounds where they are hatched. It is my 

 opinion that they have to shift for themselves from the 

 day of their birth, as I have never yet seen old birds any- 

 where near the young ones that I have come across." It 

 would be of great interest to ascertain whether these young 

 megapodes show an instinctive response to their appropriate 

 food that in other birds is absent or less marked. But 

 though the fact of their finding their own food without 

 guidance from the mother bird, may lead one to surmise 

 that this will be found to be the case, we must remember 

 that they may be guided, like hand-reared chicks, by the 

 results of experience after trying the various objects that 

 are presented to their choice. 



It would seem then that, though the evidence is by no 

 means all that could be desired, what there is suggests that 



