DOMINATING CUCKOOS 
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species depositing an egg in nests of other birds. 
In one case a prolific Cuckoo opened her season 
by twice making use of Sedge Warblers’ nests 
before the Reed Warblers had begun to build. 
Later, the same Cuckoo used a Lesser Redpoll’s * 
nest, certainly owing to the fact that all Reed 
Warblers’ nests with eggs had recently been re- 
moved. She also victimised a Marsh Warbler’s 
nest, but whether from choice or necessity was 
not noticed. I believe it to be usual for Reed 
Warbler Cuckoos to ignore totally even the Sedge 
Warblers breeding in their areas. 
Of the possibility of there being Cuckoos which 
will willingly and indiscriminately victimise any 
species of small bird with which they may meet, 
there is little or no evidence. Until I see an 
undoubtedly genuine series of eggs, laid in one 
season on one territory by one Cuckoo, taken from 
the nests of several species utilised at random, I 
shall hold to my belief that this kind of impartiality 
amongst dominant Cuckoos is of very slight ac- 
count, even if it exist at all. And if it does exist 
at all, I should expect to find it only in the case of 
first-year Cuckoos. 
Of late years there has been a tendency to over- 
* Linota rufescens. 
