The Cuckoos Foster-parents. 289 



All the while the labor undergone by the robins in 

 supplying the wide throat of the cuckoo with food 

 was something incredible. It was only necessary 

 to wait a very few minutes before one or other came, 

 but the voracious creature seemed never satisfied ; 

 he was bigger than both his foster-parents put to- 

 gether, and they waited on him like slaves. It was 

 really distressing to see their unrewarded toil. Now 

 no argument will ever convince me that the robin or 

 the wagtail, or any other bird in whose nest the 

 cuckoo lays its egg, can ever confound the intruding 

 progeny with its own offspring. Irrespective of size, 

 the plumage is so different ; and there is another 

 reason why they must know the two apart : the 

 cuckoo as he grows larger begins to resemble the 

 hawk, of which all birds are well known to feel 

 the greatest terror. They will pursue a cuckoo ex- 

 actly as they will a hawk. 



I will not saj- that that is because they mistake it 

 for a hawk, for the longer I observe the more I am 

 convinced that birds and animals often act from 

 causes quite distinct from those which at first sight 

 appear sufficient to account for their motions. But 

 about the fact of the lesser birds chasing the cuckoo 

 there is no doubt. Are they endeavoring to drive 

 her away that she may not lay her egg in either of 

 their nests? In any case it is clear that birds do 

 recognize the cuckoo as something distinct from 

 themselves, and therefore I will never believe that 

 the foster-parent for a moment supposes the young 

 cuckoo to be its own offspring. 



To our.eyes one young robin (meaning out of the 

 nest on the hedge) is almost identical with another 

 19 



