240 Habit and Instinct. 



not laid in a nest constructed by the cuckoo herself, but are 

 dropped in alien nests, being carried thither in the bill. 

 Sometimes an egg is turned out at the same time, but 

 whether purposely or by accident, it is hard to say. 

 Although there are instances on record of cuckoos feeding 

 their young — or in any case feeding young birds of their 

 own kind — and even of incubating eggs in an alien nest,* 

 yet, in the vast majority of cases, the foster-parents on 

 whom the egg is foisted hatch out and bring up the naked, 

 blind, broadshouldered, hollow-backed, changeling which 

 heaves out of the nest, rather perhaps from sheer size and 

 awkward random activity than of set purpose — the nest- 

 lings that of right belong there. Henry Jenner describes 

 in the " Transactions of the Eoyal Society for 1788," how 

 two cuckoos were hatched out in a hedge-sparrow's nest, 

 together with one hedge-sparrow — an egg remaining un- 

 hatched. In a few hours a contest began between the 

 two cuckoos, one of which at last succeeded in ejecting 

 the other, together with the young hedge-sparrow, and 

 the unhatched egg. Long doubted, but occasionally re- 

 described from observation, this summary ejection has 

 recently been not only watched but sketched from life by 

 Mrs. Hugh Blackburn.f The young outlaw, having thus 

 rid himself of his rivals, grows apace, and is fed, through 

 what would seem to be a strange modification of maternal 

 instinct, by the foster-parents with indefatigable zeal. 

 Miss Hayward describes and figures % a little whitethroat 

 feeding a young cuckoo of four or five times her own size. 

 Finally, contrary to what is held by many ornithologists 



* See Morris' " British Birds," vol. ii. (1852), pp. 56 and 59. 



t " Birds from Moidart and Elsewhere." 



\ " Bird Notes." Cf. the figure of the long-tailed cuckoo of New Zealand 

 and its host, the grey warbler, in Buller's " Manual of the Birds of New 

 Zealand," p. 39. 



