COMMON CUCKOW. 75 



Dr. Jenner made several experiments on different 

 nests, by repeatedly putting in an egg to the 

 young Cuckow, which was always disposed of in 

 the same manner. It is very remarkable, that 

 nature seems to have provided for this singular 

 disposition of the Cuckow, in its formation at this 

 period ; for, unlike every other newly hatched 

 bird, its back, from the scapulae downwards, is 

 very broad, with a considerable depression in the 

 middle, which seems intended by nature for the 

 purpose of giving a more secure lodgment to the 

 egg of the Hedge-sparrow, or its young one, while 

 the young Cuckow is employed in removing either 

 of them from the nest. When it is about twelve 

 days old, this cavity is quite filled up, the back 

 assumes the shape of nestling birds in general, 

 and at that time its disposition for turning out 

 its companion entirely ceases. The smallnes3 of 

 the Cuckow's egg, which, in general, is less than 

 that of the House-sparrow, seems to account for 

 her depositing it in the nests of such small birds as 

 those before mentioned. If it was deposited in 

 the nest of a bird that produced a larger egg, and 

 consequently a larger nestling, the design most 

 likely would be frustrated; the young Cuckow 

 would be unequal to the task of becoming sole 

 possessor of the nest, and might fall a sacrifice to 

 the superior strength of its antagonist. 



Several experiments have been made to ascer- 

 tain whether the Cuckow destroys or eats the 

 eggs which she finds in the nest in which she de- 

 posits her own; the result proved the contrary, 

 (as has been mentioned before) ; and in case the 



