146 Darwin and Romanes dealt ivith. 



The coot will not sit upon duck's eggs. The sense 

 of touch and smell in certain birds must be very keen : 

 for a gentleman, a friend of mine and true naturalist, 

 in Essex, has persevered with experiments with the 

 coot in this direction : he had at last the eggs both of 

 the teal and mallard carefully coloured to imitate the 

 coot's eggs, and, taking away the coot's, these ducks' 

 eggs were carefully substituted. But the wary coots 

 were not to be done : in all cases they abandoned the 

 nests and at once set about laboriously building others 

 at different parts of the pond side, and nothing would 

 tempt either of them back again, though their own 

 eggs were restored. They would not be tempted to go 

 near the nests nor look at them. The argument 

 suggested by these facts is exactly on all fours with 

 that from the woodpecker and the thrush's egg. And 

 one question which arises here is important indeed. 

 If the woodpecker in the dark is able so decisively 

 to detect the egg of a thrush about the same form and 

 size as its own, and to deal with it effectively, why is 

 it that so many birds fail to discriminate, and in their 

 open nests with full light to aid them, between a 

 cuckoo's egg, which is much bigger frequently and 

 almost always a little bigger, than their own eggs, 

 and will adopt it and hatch it, and at great labour, 

 rear the alien nestUng, to the utter destruction of 

 their own brood, their instinct or intelligence just 

 there failing to protect the species. Is the one 

 instinct a lack of instinct or a " misleading instinct " 

 — which ? They cannot both spring from the same 

 source. Besides all which, the little birds many of 

 them must have had experience and have utterly 

 failed to profit by it ; while the woodpecker, with no 



