104 NATURAL SELECTION v 



How do Young Birds learn to Build their first Nest ? 



But it is objected, birds do not learn to make their nest as 

 man does to build, for all birds will make exactly the same 

 nest as the rest of their species, even if they have never seen 

 one, and it is instinct alone that can enable them to do this. 

 No doubt this would be instinct if it were true, and I simply 

 ask for proof of the fact. This point, although so important 

 to the question at issue, is always assumed without proof, 

 and even against proof, for what facts there are, are opposed 

 to it. Birds brought up from the egg in cages do not make 

 the characteristic nest of their species, even though the 

 proper materials are supplied them, and often make no nest 

 at all, but rudely heap together a quantity of materials ; and 

 the experiment has never been fairly tried of turning out a 

 pair of birds so brought up into an enclosure covered with 

 netting, and watching the result of their untaught attempts at 

 nest-making. With regard to the songs of birds, however, 

 which is thought to be equally instinctive, the experiment 

 has been tried, and it is found that young birds never have 

 the song peculiar to their species if they have not heard it, 

 whereas they acquire very easily the song of almost any 

 other bird with which they are associated. 



Do Birds sing by Instinct or by Imitation ? 

 The Hon. Daines Barrington was of opinion that " notes 

 in birds are no more innate than language is in man, and 

 depend entirely on the master under which they are bred, as 

 far as their organs will enable them to imitate the sounds which 

 they have frequent opportunities of hearing." He has given 

 an account of his experiments in the Philosophical Transactions 

 for 1773 (vol. Ixiii.) He says : "I have educated nestling linnets 

 under the three best singing larks the skylark, woodlark, and 

 titlark, every one of which, instead of the linnet's song, 

 adhered entirely to that of their respective instructors. 

 When the note of the titlark linnet was thoroughly fixed, I 

 hung the bird in a room with two common linnets for a 

 quarter of a year, which were full in song; the titlark 

 linnet, however, did not borrow any passage from the 

 linnet's song, but adhered steadfastly to that of the titlark." 



