FIRST SEASON (1918): RECORD 15 
nature supporting a growth of young gorse and 
bracken varied by barer patches where at one time 
and another the common has been set on fire by 
mischievous village children.* Greatest advantage 
of all is that it is an isolated breeding ground of 
Meadow Pipits, the chosen fosterers of the Cuckoos 
in occupation. There is no other breeding ground 
of this species within a nearer distance than three 
miles, and this became a source of particular 
gratification to me, for I was quickly impressed with 
the evidence in favour of female Cuckoos occupying 
particular territories in which they are, so far as 
circumstances permit, parasitic upon a single 
species. 
In this 1918 season I only devoted to the search 
such days as opportunity offered from June 3 
onwards. On the evening of that day I had not 
been on the common for more than half an hour, 
when I flushed a Meadow Pipit from a nest con- 
taining two of her own eggs and one of a Cuckoo. 
(Henceforward I shall refer to this bird as Cuckoo A, 
and, when necessary, distinguish any of her eggs 
by a small numeral following the capital letter.) 
The three eggs were taken, and the Pipit subse- 
quently laid two more in the empty nest and then 
* See plans, pp. 106, 150, and photograph facing p. 14. 
