64 Wizard Cuckoos 



are now repeated, and we can detect how they 

 are all derived from the gabbled note of " cack- 

 cack-cack," which is itself the repetition of a single 

 inarticulate cry. From these rude elements the 

 voice is developed with the increasing vitality of 

 the nesting season through several stages, each 

 gaining in clearness of tone until it reaches the 

 perfect call, with its strange power of carrying 

 memory backwards. 



