58 Wizard Cuckoos 



experiments among the nests in any shrubbery, 

 birds vary a good deal in their attitude towards 

 windfalls of this sort. Many will placidly accept 

 an egg not too outrageously disproportionate in 

 size to their own, while others will throw it out or 

 desert the nest, or sometimes both. Probably 

 the cuckoo sometimes defeats her purpose when 

 she puts her egg in an empty nest. A cuckoo's 

 egg has been found buried under the nest's thickened 

 lining an incident which suggests that not every 

 bird is willingly the dupe of the cuckoo in the 

 earlier stages of the deception. 



But as soon as the young cuckoo is hatched, the 

 normal increase of attachment to the living young 

 makes the foster-parents the most infatuated 

 guardians of this " feverish, sharp-toothed child." 

 From within a few hours of its birth the copper- 

 coloured imp seems filled with a frenzied passion of 

 growth, as though intensely aware of the swift 

 development it must make from its disproportion- 

 ately small beginnings. Actual teeth it has not ; 

 but long before it learns to make its later lively 

 use of beak and claws, and while it is still as blind 

 and naked as a penny, it effectively gets rid of the 

 rivals which it cannot see, but can feel, by use of 

 its special weapons. These are a marvellously 

 precocious vigour and dexterity, and an unusually 

 broad and concave back. Jenner, the Berkeley 

 doctor who discovered vaccination, was one of 

 the earliest recorded observers of the process by 

 which the young cuckoo throws the other nestlings 

 out of the nest, and has left an accurate account 



