REMOVAL OF EGGS 
207 
It will be remembered that when dealing with 
the thirteenth egg of Cuckoo A in 1920, I advanced 
reasons for supposing that the fosterer had removed 
one of her own eggs, deserting the nest before the 
Cuckoo deposited her egg therein. Later, there 
can be little doubt, this same fosterer removed 
one of her own eggs from the nest in which the 
Cuckoo deposited her twenty-first egg. This 
action is obviously one of resentment against 
visits of the Cuckoo, which the dupe probably 
associated, by prior experience, with the eventual 
loss of all her eggs. Doubtless it will be asked 
why the dupe should have been satisfied with the 
removal of one egg only, and did not return for the 
rest ? The only answer to this seems to be that 
her resentment was appeased by taking away one, 
and she ceased to trouble further about those 
remaining, merely deserting them. It is a curious 
performance, but one which is likely to have come 
within the experience of most field-oologists, 
though probably their own interference, and not 
that of the Cuckoo, has been the cause of the bird's 
action. There are few who cannot recall instances 
of the discovery of incomplete clutches, and of 
then returning to find that not only had the eggs 
been deserted, but were short of the number 
