THE PIED CRESTED CUCKOO 53 



selectionist has still to prove that the characteristic 

 had this value at the earliest, and at each successive 

 stage of its development. 



I submit, then, that the Wallaceian's explanation 

 of the hawk-like appearance of the brain-fever bird is 

 in all probabihty not the correct one. In the same way 

 it is doubtful whether the blue eggs of the brain-fever 

 bird and the pied crested cuckoo can be fairly laid to 

 the charge of natural selection. The common cuckoo 

 sometimes lays its eggs, which are not blue, in the nests 

 of birds whose eggs are blue, for example the hedge- 

 sparrow in England and the Himalayan laughing thrush 

 in India. 



The pied crested cuckoo, when it first leaves the 

 nest, differs considerably from the adult in appear- 

 ance. Its upper parts are slaty grey, and its lower 

 parts, the wing patch and the tips of the outer tail 

 feathers are pale buff, so that the young cuckoo, when 

 flying, might easily be mistaken for a bank myna 

 (Acridotheres ginginianus) but for the length of its 

 tail. Like all young cuckoos, it is a greedy, querulous 

 thing. It sits on a branch, clamouring continually for 

 food, flapping its wings and uttering a very fair imita- 

 tion of the babbler call. 



September is the month in which to look out for 

 young pied cuckoos. Those that I have seen appear 

 always to be unaccompanied by foster-brothers or 

 sisters. This would seem to indicate either that the 

 parent cuckoos destroy the legitimate eggs at the time 

 of depositing their own, or that the young birds have 

 the depraved habits of the youthful Cucuhis canorus. 



