204 BIRDS OF THE PLAINS 



out our friend the drongo cuckoo as an example of 



mimicry. The mimicry is, of course, unconscious : 



it is said to be the result of the action of natural 



selection. 



King-crows are, as every one knows, exceedingly pug- 

 nacious birds ; at the nesting season both cock and hen 

 are little furies, who guard the nursery most carefully 

 and will not allow a strange species to so much as perch 

 in the tree in which it is placed. 



It is thus obvious that the cuckoo who elects to victim- 

 ise a king-crow is undertaking a "big thing," yet this 

 is what Siirnicidus does. It accomplishes its aim by 

 trickery ; it becomes a gay deceiver, disguising itself like 

 its dupe. Now I readily admit that the disguise may be 

 of the utmost use to the Siirnicidus ; I can well under- 

 stand that natural selection will seize hold of the dis- 

 guise when once it has been donned and possibly perfect 

 it ; but I cannot see how natural selection can have 

 originated the disguise as such. 



The drongo cuckoo may be called an ass in a lion's 

 skin, or a lion in an ass's skin, whichever way one looks 

 at things. When once the skin has been assumed 

 natural selection may modify it so as better to fit the 

 wearer ; but more than this it cannot do. 



I do not pretend to know the colour of the last com- 

 mon ancestor of all the cuckoos, but I do not believe 

 that the colour was black. What, then, caused Surni- 

 culus liigubris to become black and assume a king-crow- 

 like tail ? 



A black feather or two, even if coupled with some 

 lengthening of the tail, would in no way assist the 



