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 Instinet 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. lxiii.) 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.” 
