A YOUNG CUCKOO 71 



its eggs, so that this portion of the subject at any 

 rate need no longer remain an ornithological toy. 



In leaving this portion of the subject, I should 

 add that I have examined seventy-six nests, 

 representing thirty-one species of birds, containing 

 Cuckoos' eggs. The alleged specialisation into 

 types approximating to the types of eggs laid by the 

 foster-parents shows no constancy, the difference 

 between the Cuckoo's egg laid in one nest and that 

 laid in another nest of birds of the same species 

 being as great as between the Cuckoos' eggs laid in 

 the nests of two birds of different species. Indeed, 

 I have seen few Cuckoo's eggs, however different 

 the species of birds in whose nests they were laid, 

 that differed more widely than the egg to be seen in 

 the nest of a Pied Wagtail in the Museum of Owens 

 College, at Manchester, and the Cuckoo's egg I took 

 with one of those of the foster-parent from a nest of 

 the same species at Mobberley, Cheshire. 



The variation exhibited in the collections I have 

 seen was considerable, but I could in most cases have 

 improved the assimilation by transferring the eggs 

 from one nest to another. Unless more convincing 

 evidence were brought forward than such as was 

 furnished by the seventy-six nests mentioned above, 

 I should conclude that cases of resemblance between 

 Cuckoos' eggs and those of the species in whose nests 

 they are deposited, are due to coincidence rendered 

 possible by a large degree of variation in the former. 

 Instances in which there is no such resemblance 

 preponderate. Different minds, I know, will draw the 

 line between resemblance and lack of resemblance 

 in different places ; but, wherever it be drawn, upon 



