320 BIRDS OF INDIA. 



tail rounded, nearly square, sub-furcate in one group ; tibial fea- 

 thers lengthened ; tarsus very short, partly feathered ; feet small ; 

 outer toe capable of being directed either backwards or sideways. 



The true Cuckoos are exclusively inhabitants of the Eastern 

 hemisphere, and are especially numerous in India and Malayana. 

 They may be sub-divided into two principal groups or sections, 

 one with the plumage generally barred beneath, and no trace of 

 eye-lashes ; the other. without any barring, a series of plumelets in 

 place of eye-lashes, and the colour generally dark. 



To this sub-family almost exclusively belongs the remarkable 

 habit, celebrated from all ages, of the female bird depositing her 

 eofcrs in the nests of other birds to hatch and bring up. This habit 

 is only found, elsewhere, in the Molothrus, an American genus, 

 usually placed among the Starlings ;* but the American Cuckoo, 

 though it ordinarily incubates its own eggs, and feeds its progeny, 

 does sometimes adopt the procedure of the old world Cuculince. 

 The eggs of the parasitic Cuckoos appear to approximate^ both in 

 size and colour, those of the birds into whose nests they are depo- 

 sited. Only one Qgg, in general, is placed in each nest; and some of the 

 eggs, at all events of the rightful owner, are ejected at the same 

 time ; the newly-hatched Cuckoo is also known to hoist its nestling 

 companions, if any, on its back and eject them from the nest, so as to 

 ensure a more plentiful supply of food for its own increasing wants. 



The causG of this peculiar habit is supposed to be, that the oggs 

 of the Cuckoo are matured very slowly, and that she requires an 

 interval of several days to elapse between the laying of each egg ; 

 and the young, too, require to be fed longer than the young of 

 other birds ; which circumstances combined, would make it difficult 

 for her to incubate her own eggs, and rear the brood. It may be 

 that from want of intelligence she is unable to construct a nest. 

 The low development of the parts subservient to generation, the 

 small eggs of some, and a weakening of the parental impulses, 

 which is likely enough to accompany this, have been supposed to 

 afford an explanation of their peculiar habits ; but some of the 

 parasitic Cuckoos, the species of Coceystes among others, lay 

 ordinarily-sized eggs. 



* The Australian genus Scythrops, among the PhenicophaincE, is another exception. 



