May lis 



the perpetuation of its species, these eggs must not be 

 left to rot on the ground. Wherefore she lays eggs 

 preposterously small in comparison with her own bulk 

 — so small that they may be tucked conveniently into 

 the nest of some guileless wagtail, meadow-pipit, reed- 

 warbler, hedge-sparrow, or the like, where they are sure 

 to receive from an alien bosom the warmth and shelter 

 necessary for incubation. Having distributed her full 

 number of eggs (observers differ in their estimate of the 

 average number laid), each in a different nest, she takes 

 no more thought for her prospective brood, but flies off 

 to enjoy the summer, until, towards the end of July, 

 when the supply of caterpillars begins to dwindle, she 

 departs for the sunnier south in company with her 

 frivolous friends. I think there are no old cuckoos to 

 be seen after mid- August ; only birds hatched in the 

 current season. 



It is natural to feel surprised that the cuckoo should 

 lay so small an egg, the parent being three times the 

 size of a snipe, and a snipe's egg at least six times the 

 bulk of a cuckoo's. The reason, however, is pretty 

 clear. A cuckoo's egg is small in order that it may be 

 slipped in among the eggs of a bird much smaller than 

 herself without arousing suspicion. But why, it may 

 be asked, should the cuckoo choose birds far smaller 

 than herself as foster parents for her young? The 

 answer is furnished by the darkest trait in all this 

 career of immorality. It is necessary that the nestling 

 cuckoo should be more powerful than any of his foster 

 brothers and sisters, so that he may be able, with back 

 and shoulders specially adapted for this dire purpose, 



H 



