122 Instinct and its Lessons 



that this experiment has been tried, 1 but naturalists of 

 an experimental turn have often put the eggs of one 

 bird in the nest of another. Thus Waterton writes to 

 Mr. Ord, July 4, 1833: "This season I have made 

 Jackdaws hatch Magpies, and Magpies Jackdaws ; 

 Carrion Crows have brought up Rooks, and Rooks 

 Carrion Crows. It is quite laughable to see a brood of 

 young Jackdaws following an old Magpie, and vice 

 versa" Does any one for a moment suppose that when 

 mature these birds would not instinctively know their 

 own kind, and next season build their nests after its 

 fashion, though, in the case, for instance, of the Jackdaw 

 and Magpie, totally different from that in which they 

 have been reared ? 



It must also be allowed that even supposing a young 

 bird to occupy his leisure with inspection of the domicile 

 in which he lies, he will need something like instinct, 

 and plenty of it, to compose a similar one, when his own 

 time comes. Mr. Wallace 2 implies that the instinctive 

 character of birds' architecture is discredited by the 

 observation that they severally employ the materials that 

 naturally lie in their way : thus the thicket-dwelling 

 Wren uses moss ; Kingfishers, fish bones ; Carrion Crows, 

 fur or wool ; the earth-grubbing Rook, fibrous roots ; and 

 the pool-haunting Swallow, mud and clay. But is this 

 quite a fair account of the matter? To say nothing of 

 the Tailor birds and Weaver birds of other climes, we 

 find most remarkable instances amongst our own species, 

 of materials both carefully chosen and artistically used. 

 The Bottle-tit, besides moss for the walls of his structure, 

 and feathers for the lining, weaves the whole together 

 with fine threads of wool, felts the dome, and makes it 

 rain-proof, with moss and lichens, wool, and the web of 

 spiders' eggs; and coats the outer surface with white 



1 Since writing the above, I have been informed that bird-fanciers 

 are in the habit of substituting an artificial nest for that built by 

 Canaries ; and that the young so reared nevertheless build after the 

 manner of their species. 



' 2 Natural Selection^ p. 216. 



