THE LAYING OF CUCKOOS 177 
her to victimise, my opinion being that a Cuckoo 
will tend to deposit her eggs in the nests of that 
species in which her mother placed her eggs, or, 
in other words, her natural fosterers. 
I know that the theory is original, and is 
challenged in some quarters eminently worthy of 
respect. For this reason I am desirous of making 
my meaning perfectly clear, and so will adduce 
evidence we have in support, although previous 
chapters may almost be said to have bristled with 
it. Here are some examples — 
(1 a ) The nest in which the tenth egg of Cuckoo 
A was laid on May 31, 1920, was seen to 
be visited by the Cuckoo two days before, 
i.e. on May 29, when it contained one egg. 
(b) The Cuckoo was seen to fly on May 30, 
1920, from the site of the nest in which 
on June 2 the Cuckoo’s eleventh egg was 
seen to be deposited. 
( c ) The nest in which her eighteenth egg was 
laid on June 18, 1920, was seen to be 
visited by the Cuckoo on June 15, when 
it contained two eggs. 
( d ) The nest in which her twentieth egg was 
laid on June 22, 1920, was seen to be 
visited by the Cuckoo six days previously 
(on June 16), when it contained one egg. 
N 
