90 BIKDS 



BLACKBIRD-MORALITY 



The following uncommon, if not unique, incident came 

 under my observation this week. A pair of thrushes have 

 built a nest in the ivy against the wall of my house. 

 Early one morning I found there were four eggs in it. 

 Half an hour later I saw a hen blackbird drive the thrush 

 off the nest and take possession herself. By midday a 

 blackbird's egg was deposited in the nest and one of the 

 thrush's eggs was lying on the ground broken. The fol- 

 lowing morning the thrush again took possession, laid 

 another egg in the nest, and is now patiently sitting on 

 four eggs of its own and the intruding blackbird's egg. 

 What was the motive of the blackbird? Had it no nest 

 of its own? Is it developing similar tendencies to the 

 cuckoo and placing its eggs in the nests of other birds? 

 It is a curious problem. 



JOHN W. SELLER. 



May 24, 1913. 



NOTE. These two letters are of striking interest. They 

 indicate in the first place the marked differences in 

 character between individual birds of the same species 

 a difference noticeable even in the quality of their songs 

 and one which warns the naturalist not to be too facile 

 in his generalizations of the habits of a species from the 

 conduct of one of its members and in the second that 

 the peril of parasitism which we can quite legitimately 

 call the temptation to sin is common to every species. 

 Among our British birds only the cuckoo has succumbed 

 to it, while the American cuckoo, who sometimes broods 

 her eggs and rears her young like a respectable bird, and 

 sometimes not, has compromised with the devil ! If the 

 cuckoos only took the wrong turning, we might argue that 

 cuckoos and crime always went together like waiters and 

 white shirts. But other people besides waiters wear white 

 shirts and other families besides cuckoos are prone to baby- 



