THE CUCKOO. 227 



return to the same locality, and build its nest in 

 almost the same spot. Though the Cuckoo be 

 somewhat of a vagrant, there is no improbability 

 of her being subject to thus much regularity of 

 habit, and indeed such has been asserted as an 

 observed fact. If, then, this be so, there is every 

 probability of her offspring inheriting the same 

 habit, and the daughter of a Cuckoo which always 

 placed her egg in a Reed Wren's or a Titlark's 

 nest doing the like." In other words, the habit 

 of depositing an egg in the nest of a particular 

 species of bird is likely to become hereditary. 



This would be an excellent argument in sup- 

 port of the theory, were it not for one expres- 

 sion, upon which the whole value of the argu- 

 ment seems to me to depend. What is meant 

 by the expression "once successfully deposited" ? 

 Does the Cuckoo ever revisit a nest in which 

 she has placed an egg, and satisfy herself that 

 her offspring is hatched and cared for .i* If not 

 (and I believe such- an event is not usual, if 

 indeed it has ever been known to occur), then 

 nothing has been gained by the selection of a 

 Reed Wren's or Titlark's nest (as the case may 



