The Making of Species 



unless one is near enough to see the beak, or can 

 watch the bird settle and note the difference 

 between the horizontal pose of the cuckoo and 

 the erect bearing of the hawk, it is impossible to 

 tell them apart on a casual view." Moreover, 

 the tail of the cuckoo sometimes hangs down 

 vertically, thus intensifying the likeness to the 

 hawk. 



It is quite possible that the brain-fever bird 

 derives some benefit from the resemblance ; 

 indeed, it has been seen to alarm small birds, 

 even as the hawk-like common cuckoo frightens 

 its dupes, but, as D. Dewar pointed out, on page 

 105 of vol. 57 of the Journal of the Society of 

 Arts, " this is not sufficient to explain a likeness 

 which is so faithful as to extend to the marking 

 of each individual feather. When a babbler 

 espies a hawk-like bird, it does not wait to inspect 

 each feather before fleeing in terror ; hence all 

 that is necessary to the cuckoo is that it should 

 bear a general resemblance to the shikra. The 

 fact that the likeness extends to minute details in 

 feather marking, points to the fact that in each 

 case identical causes have operated to produce 

 this type of plumage." This conclusion is still 

 further strengthened by the fact that the likeness 

 extends to the immature plumage, that is to say, 

 exists at a time when it cannot assist the cuckoo 

 in its parasitical work. 



Poulton meets this objection as follows : 

 236 



