VOL. LXXVm.] PHILOSOPHICAL TRANSACTIONS. 435 



out the cuckoo, and placed the egg containing the hedge-sparrow in the nest in 

 its stead. The old birds during this time flew about the spot, showing signs of 

 great anxiety; but when I withdrew they quickly came to the nest again. On 

 looking into it in a quarter of an hour afterwards, I found the young one com- 

 pletely hatched, warm and lively. The hedge-sparrows were suffered to remain 

 undisturbed with their new charge for 3 hours, during which time they paid 

 every attention to it, when the cuckoo was again put into the nest. The old 

 sparrows had been so much disturbed by these intrusions, that for some time 

 they showed an unwillingness to come to it : however, at length they came, and 

 on examining the nest again in a few minutes, I found the young sparrow was 

 tumbled out. It was a 2d time restored, but again experienced the same fate. 

 From these experiments, and supposing, from the feeble appearance of the 

 young cuckoo, just disengaged from the shell, that it was utterly incapable of 

 displacing either the egg or the young sparrows, I was induced to believe that 

 the old sparrows were the only agents in this seeming unnatural business; but I 

 afterwards clearly perceived the cause of this strange phenomenon, by discover- 

 ing the young cuckoo in the act of displacing its fellow-nestlings, as the follow- 

 ing relations will fully evince. 



June 18, 1787, I examined the nest of a hedge-sparrow, jwhich then con- 

 tained a cuckoo's and 3 hedge-sparrow's eggs. On inspecting it the day following 

 I found the bird had hatched, but that the nest now contained only a young 

 cuckoo and 1 hedge-sparrow. The nest was placed so near the extremity of a 

 hedge, that I could distinctly see what was going forward in it ; and to my 

 astonishment, saw the young cuckoo, though so newly hatched, in the act of 

 turning out the young hedge-sparrow. The mode of accomplishing this was 

 very curious. The little animal, with the assistance of its rump and wings, 

 contrived to get the bird on its back, and making a lodgement for the burden by 

 elev^ating its elbows, clambered backward with it up the side of the nest till it 

 reached the top, where resting for a moment, it threw off its load with a jirk, 

 and quite disengaged it from the nest. It remained in this situation a short 

 time, feeling about with the extremities of its wings, as if to be convinced whe- 

 ther the business was properly executed, and then dropped into the nest again. 

 With these, the extremities of its wings, I have often seen it examine, as it were, 

 an egg and nestling before it began its operations; and the nice sensibility which 

 these parts appeared to possess seemed sufficiently to compensate the want of 

 sight, which as yet it was destitute of I afterwards put in an egg, and this, by 

 a similar process, was conveyed to the edge of the nest, and thrown out. These 

 experiments I have since repeated several times in different nests, and have 

 always found the young cuckoo disposed to act in the same manner. In climb- 

 ing up the nest, it sometimes drops its burden, and thus is foiled in its endea- 



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