PDF - Wallace Online

104 NATURAL SELECTION vHow do Young Birds learn to Build their first Nest ?But it is objected, birds do not learn to make their nest asman does to build, for all birds will make exactly the samenest as the rest of their species, even ifthey have never seenone, and it is instinct alone that can enable them to do this.No doubt this would be instinct if it were true, and I simplyask for proof of the fact. This point, although so importantto the question at issue, is always assumed without proof,and even against proof, for what facts there are, are opposedto it. Birds brought up from the egg in cages do not makethe characteristic nest of their species, even though theproper materials are supplied them, and often make no nestat all, but rudely heap together a quantity of materials ;andthe experiment has never been fairly tried of turning out apair of birds so brought up into an enclosure covered withnetting, and watching the result of their untaught attempts atnest-making. With regard to the songs of birds, however,which is thought to be equally instinctive, the experimenthas been tried, and it is found that young birds never havethe song peculiar to their species if they have not heard it,whereas they acquire very easily the song of almost anyother bird with which they are associated.Do Birds sing by Instinct or by Imitation ?The Hon. Daines Barrington was of opinion that " notesin birds are no more innate than language is in man, anddepend entirely on the master under which they are bred, asfar as their organs will enable them to imitate the sounds whichthey have frequent opportunities of hearing." He has givenan account of his experiments in the Philosophical Transactionsfor 1773 (vol. Ixiii.)He says: "I have educated nestling linnetsunder the three best singing larks the skylark, woodlark, andtitlark, 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, Ihung the bird in a room with two common linnets for aquarter of a year, which were full in song; the titlarklinnet, however, did not borrow any passage from thelinnet's song, but adhered steadfastly to that of the titlark."