358 On the European Cuckoo and its Indian Allies. 



In the third stage the whole upper plumage, wings, and tail 

 are bright chestnut barred with black ; the lower plumage is 

 very regularly barred with black, and the throat and breast 

 are tinged with deep chestnut ; the nuchal spot and the half- 

 collar are absent. 



In attaining mature plumage, the black bars on the neck, 

 rump, and upper tail-coverts are the first to disappear and to 

 give place to ashy patches. 



It is sufficiently evident from the above descriptions that 

 the young of the three species are quite distinct in coloration, 

 taking birds of the same age together for comparison, and 

 that in some stages there is a plumage which cannot be 

 matched by any other stage of either of the other species. 



To render these remarks of some practical utility it will be 

 necessary now to focus the differences and to point out how 

 they may be of service in determining the species when 

 young birds only are under examination. 



In the young nestling-stage, when size goes for nothing, 

 and the wing is not grown to allow of measurement, the 

 white nuchal spot will separate C canorus from the other two 

 Cuckoos. This spot will also at all ages serve to separate 

 it from C. striatus, but not from C. poliocephalus, from which 

 latter, however, it can be distinguished, when the nuchal 

 spot is no longer a character, by its much greater size and 

 pale rufous coloration. 



C. striatus and C. poliocephalus in the mere nestling-stages 

 cannot, I think, be separated except by size ; but once the 

 nuchal spot and the half-collar are assumed by the latter 

 there is no difficulty whatever. 



All three birds, in their rufous stage, are easy to separate : 

 C. canorus is pale rufous ; C. striatus dark rufous, with 

 coarse bars ; and C. poliocephalus chestnut, delicately barred. 



I do not put forward the above characters as infallible. I 

 merely wish to point out that in all three species the young 

 pass through peculiar phases of plumage, which show them 

 to be very distinct. It would not be difficult to find a 

 young bird now and again the plumage of which sets these 

 general laws at defiance ; but I consider that, interpreted 



I 



