Nest-Building 165 



for food, repeatedly offer them grass and sticks before producing 

 the fish which they carry in their stomachs or after having fed 

 them, gather a mass of grass, carry it away, and deposit it at 

 the foot of a stump, as they do when actually building a nest. 



It is thus plain that in such actions we have the expression 

 of a great variety of emotions. In some cases they lead to the 

 repair and temporary occupation of old nests at the close of 

 the season, when for days at a time the old birds, as if with 

 instincts imperfectly satisfied, will incubate an addled egg. It 

 is not improbable that in such sporadic actions, as in the more 

 serious work of actual nest-building, similar emotions are ex- 

 pressed in a similar way. 



At all events this behavior of the Gull sheds light on the 

 reputed intelligence and forethought of the Ospreys, which are 

 said to repair their nests at the close of summer in anticipation 

 of the coming year. This casual return of the nest-building 

 instinct is undoubtedly the same in the Hawk, Eagle, or Gull, 

 and implies no more forethought in one than in the other. I 

 think we can understand why some birds, like Robins and 

 Phoebes, occasionally build more than one nest, and, unlike the 

 Gulls, build them together and in the same spot. Their instinct 

 is not satisfied with the building of a single nest. 



The philosophy of nest-building is set forth in a new light 

 by the study of the Gulls and Terns. Mr. Wallace once main- 

 tained that the young of wild birds learned enough about their 

 nests in infancy to enable them to reproduce the same type of 

 architecture when they came to rear offspring of their own. 

 It was also affirmed that the beginner in this art received aid 

 by mating with an older bird. The first notion is not to be 

 taken seriously, and in support of the second the testimony 

 is insufficient. It is now almost universally admitted that 

 the initial steps in nest-building are in every case instinctive, or 

 independent of experience. 



It is impossible to suppose that young birds have concep- 

 tions of any kind, or are able to distinguish their artificial nest 



