BIRDS IN THE CALENDAR 
deliberate notice of the size or colour of their 
own eggs. Kearton somewhere relates how 
he once induced a blackbird to sit on the eggs 
of a thrush, and a lapwing on those of a red- 
shank. So, too, farmyard hens will hatch the 
eggs of ducks or game-birds and wild birds 
can even be persuaded to sit on eggs made of 
painted wood. Why then, since they are so 
careless of appearances, should the cuckoo 
go to all manner of trouble to match the eggs 
of hedgesparrow, robin or warbler ? The bird 
would not notice the difference, and, even if 
she did, she would probably sit quite as close, 
if only for the sake of the other eggs of her 
own laying. Once the ugly nestling is hatched, 
there comes swift awakening. Yet there is 
no thought of reprisal or desertion. It looks 
rather as if the little foster-parents are hyp- 
notised by the uncouth guest, for they see 
their own young ones elbowed out of the home 
and continue, with unflagging devotion, to 
minister to the insatiable appetite of the 
greedy little murderer. A bird so imbued as 
the parasitic cuckoo with the Wanderlust 
would make a very careless parent, and we 
must therefore perhaps revise our unflattering 
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