82 Further Facts and some Results. 



have found that, generally, in each case when a 

 strange egg is put into a nest before the owner of it 

 had begun to lay, that nest is deserted — if it be placed 

 along with the owner's eggs, it is very commonly 

 ejected, but if substituted for the latter, then the 

 duped bird will lay other eggs to it and sit on all." * 



I am inclined to think there is much more in this 

 suggestion than has yet been realised. And my idea 

 is, in so far, not theoretic, but practical : I have twice 

 seen hen cuckoos flying away with shells or pieces of 

 shells from nests — one that of a pied wagtail, and the 

 other that of a robin redbreast, in each of which, 

 certainly, there was found, on looking, a cuckoo's 

 egg. The bird had broken an egg in the nest, sucked 

 out the contents, and was carrying away the shell — 

 just as a bird would do in the ordinary course after 

 hatching, and as I have seen them do hundreds of 

 times. My idea is that from observing this arose the 

 idea that the cuckoos were egg-suckers, which, I 

 believe, they are — but only now-a-days under the 

 necessity of effecting the abstraction of an egg from 

 the nest to make a place for their own egg, and so 

 more perfectly dupe the victim. It is known now 

 that the cock cuckoo habitually assumes his most 

 hawk-like form, as Dr. Bowdler Sharpe by one case 

 has illustrated, to drive away all birds from about the 

 selected nest ; this would be the more necessary if 

 more were needed than merely to drop an egg in from 

 the bill — the work only of an instant. 



We have confirmatory evidence on this from a 

 good authority : 



" Some observers state that the hen cuckoo always 



* Asiatic Soc. Jrl., 1842, p. 4. 



