PLAYING CUCKOO 



ORNITHOLOGICAL experience led me 

 some time back to the belief that at the 

 nesting season a bird becomes a creature 

 of instinct, an organism whose actions are, 

 for the time being, those of a machine, a mere auto- 

 maton. This view, which has been set forth in the 

 preceding article, is not held by all naturalists. I there- 

 fore determined to undertake a systematic series of 

 experiments with a view to putting it to the test. In 

 other words, I decided to play cuckoo. I selected the 

 Indian crow (Corvus splendens] as the subject of my 

 experiments, because it is the most intelligent of the 

 feathered folk. If it can be proved that when on the 

 nest the actions of this bird are mechanical, it will follow 

 that the less intelligent birds are likewise mere automata 

 when incubating. Another reason for selecting the crow 

 as my victim is that I have been investigating the 

 habits of the koel (Eudynamis honorata), which is para- 

 sitic on the crow, and in so doing have had to visit a 

 large number of crows' nests. 



The crow lays a pale blue egg blotched with brown, 

 while the egg of the koel is a dull olive-green also blotched 

 with brown. It is considerably smaller than the crow's 

 egg. I have seen dozens of koel's eggs, but never one that 



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