THIRD SEASON (1920) : RECORD 53 
Now Cuckoo A laid these first four eggs before 
our operations had become sufficiently well 
organised to admit of the finding of the nests before 
the deposition of the Cuckoo’s eggs. Thus it was 
that at mid-day on Friday, May 21, we found a 
nest of what we subsequently identified as No. 5 
pair of Meadow Pipits ; it contained three fresh 
eggs of the fosterer. At that stage of our inquiry 
we laboured under the delusion that the Cuckoo 
in all probability laid, like her dupes and in fact 
most birds, in the early morning. Consequently 
we did not trouble to visit the nest again until 
about 9 a.m. the next day. Upon finding that it 
then contained Cuckoo A’s fifth egg, we wrongly 
assumed that she had laid it that morning, whereas, 
to judge by subsequent experience, it must have 
been laid on the previous afternoon. The nest 
contained three eggs of the fosterer as well as that 
of the Cuckoo. From the fact that the fosterer 
laid a fifth egg next day, this showed that the 
Cuckoo had removed one and that the Meadow 
Pipit had added her fourth egg that morning. 
At that time, Saturday, May 22, we were not 
aware that we had found all the nests then available, 
and consequently we had no reason to expect to 
find that Cuckoo’s egg where we did. The only 
