YOUNG BIRDS IN THE NURSERY 71 



movement of the upper jaw forcing out little jets of water 

 bearing sand and mud, and leaving the shell-fish behind. 

 The work of selection is done partly by means of the 

 large fleshy tongue, and partly by strainers, such as fringe 

 the mouth of many species of ducks, and form the whale- 

 bone of whales. These shell-fish, in places, seem to lie 

 half-buried in mud, and in such cases they are released 

 by a curious treading movement of the feet. 



Now it would seem that the changed manner of feeding, 

 displayed by the nestling just referred to, is instinctive, 

 for captive nestlings kept by Mr. Chapman would " dance " 

 the rice on which they were fed from the bottom of their 

 feeding dish in order that they might the more easily 

 secure it. It is by no means certain, by the way, that 

 shell-fish form the sole diet of this bird throughout the 

 whole of its range — which is world-wide ; and we suspect 

 that vegetable matter and small Crustacea will be found 

 to comprise no small part in most cases. 



Young birds of prey receive instruction first in the art 

 of breaking up their food, and later in its capture. Mr. 

 Macpherson, in his study of the life-history of the golden 

 eagle, has revealed more to us, on this head, in the matter 

 of birds of prey, than any other writer. At first his young 

 eagle was fed on the livers of hares, rabbits, and grouse : 

 later flesh was added ; these morsels he always took from 

 his mother's beak. But soon she began to disembowel 

 her prey in his presence, and eating the entrails herself, 

 would then present the carcase in such a way that he 

 was able to pick out the liver and other tit-bits himself. 

 Thus began his first lessons in feeding himself. On a 

 later occasion the mother returned to the nest and found 

 him calling for food with a rabbit's leg stiU beside him. 

 Apparently thinking him unreasonable, and annoyed at 



