Tlie Cuckoo Jia^ an Object. 63 



Since then there have now and again been notes 

 made by observers to the same effect. An Essex 

 naturahst, with whom I am acquainted, declares an 

 experience of the same kind. It is evident that the 

 cuckoo at one time — though a remote time — nested 

 and brooded its own eggs and young, and there is 

 surely no impossibility in reversions to original habit 

 in rare circumstances here as is found to be the case 

 in many other instances. 



If it is argued that other birds' eggs vary to a 

 much greater extent than is believed by any but 

 systematic ornithologists, it is enough to say that this 

 is beside the mark, because, so far as we know, there 

 is no object in this variation : it is matter of accident 

 or change of physical condition ; but it is wholly 

 different with the cuckoo, because in its case there is 

 an object — an object of the most definite kind. Its 

 success must depend either on the stupidity of certain 

 birds, or on its own cleverness and power of imita- 

 tion, so far as certain other birds are concerned ; and, 

 since it can never know beforehand exactly what may 

 be required of it — as witness the case of the reed- 

 warbler which buried two cuckoo's eggs because it 

 could not turn them out (and to this we shall refer 

 again) — the very existence of the race depends on 

 deception or studied colouration of eggs up to a 

 certain point, so far as certain birds' nests are used 

 by it. 



If there were no difference in the powers of birds in 

 discriminating and rejecting, the problem to our mind 

 would be much simphfied from the point of view of 

 Professor A. Newton, but he, alas ! is very clear on 

 the difference, and indeed makes all he can of it. 



