64 A YOUNG CUCKOO 



If different clans of Cuckoos really exist, is there 

 any need to invoke so remote an agency as Heredity 

 to account for them, when a more intelligible reason 

 lies at hand in the individual experience of each 

 Cuckoo ? Would not a Cuckoo that was hatched 

 and for months tended by Meadow-pipits prefer, if 

 any preference be exercised at all, the nests of 

 Meadow-pipits for the deposition of its eggs to the 

 nests of other species with which it had had no 

 relationship at all ? Such an action would be but 

 the natural continuation of its existence along the 

 line upon which it started life. 



It is in the interest of this direct appeal to each 

 Cuckoo's own experience that it is desirable to 

 determine if the young Cuckoo uses the note of its 

 foster-parents. Even if it did not use it, the hearing 

 of this note, once familiar, in later life would, through 

 association of ideas, very probably be an invitation 

 to the now grown bird ; if it were established that 

 during its foster-days the young bird itself did use 

 the note, it must in later life be even more readily 

 attracted by it. 



If the appeal to Heredity seemed unnecessary, 

 the demand made upon Natural Selection involves 

 assumptions that put a strain upon facts. 



In order to decide if there has been assimilation 

 of the Cuckoo's eggs to those of the foster-species, 

 we should need to know what was the type (or 

 types) of egg laid by the Cuckoo when first it foisted 

 its eggs upon other birds. If it were anything like 

 the average of existing types, it had not far to travel 

 in some directions ; if there were a greater difference, 

 what would become of the appeal to Natural 



