98 THE LIVING ANIMALS OF THE WORLD 



fhoto by J. Peat Miliar^ 



YOUNG CUCKOO EJECTING EGG 



T/ie egg h Jield in position by the head and ivingi 



IBtiih 



cunning, and the mutual co-operation of botli the male ami his — at least temporary — wife; 

 hence the disguise. The plan of execution very frequentl}- adopted is for the male to hover 

 over the treasure-house of the intended foster-parents hawk-wise. This is sure to call forth an 

 attack from the poor little wretches threatened, which ends in an apparently hast}- retreat of 

 the marauder, followed b)' his fearless assailants. No sooner is the coast clear, however, than 

 the wil}' female, taking her egg in her beak, slips quietly up to the nest and deposits her burden. 



Let us imagine that this home so late]}- threatened is that of the modest little hedge- 

 sparrow, and take a peep during the absence of the owners, after quiet has established itself 

 once again. Lying side by side with the tiny sk}--blue eggs of the hedge-sparrow we should 

 find the relatively large, greyish-green or reddish-gre}- egg of the cuckoo. What a contrast! 

 If the hedge-sparrows notice this too, the}- e\identl}- do not mind, for the}- in\ariabl}' hatch it 

 with their own. 



But some birds are not so accommodating as this, and would ruthlessly destroy or reject 

 any egg surreptitiously introduced into the nest. Consequently more deception has to be 

 practised. The hawk-like garb still serves its purpose to draw off the intended dupes from 

 the nest; but this is not enough, for to deposit an egg of the normal cuckoo type would be 

 worse than useless, since it would meet with instant destruction on the return of the owners 

 of the nest. But the cuckoo, strange to sa}-, has proved equal to the occasion, and meets 

 the difficulty by laying an egg to match those in the nest. The Redstart, Wagtail, Sedge- 

 warbler, Red-backed Shrike, and Meadow-pipit ma}- be cited as instances of — shall we say 

 exclusive? — birds which must be circumvented b}- " colourable imitations." Perhaps the most 

 wonderful of the cuckoo successes in this direction is the imitation of the redstart's egg, 

 which is blue. 



Naturally these facts ha\-e given rise to much speculation, but c\-cn now we cannot regard 

 the discussion as finally settled. Some ornithologists held that the egg of every individual 

 cuckoo was subject to great variations, and that the place of deposit of each egg was determined 



