v THE PHILOSOPHY OF BIRDS’ NESTS 109 
aid of an unknown and mysterious faculty to do that which 
is so strictly analogous to the house-building of savage man. 
The observations and experiments of the late Mr. Spalding 
may seem opposed to this view, as they undoubtedly prove 
some very remarkable instinctive actions on the part of young 
chickens hatched in an incubator. These birds appear to 
recognise the call of a hen; and one chick walked or ran 
straight towards her, leaping over or running round small 
obstacles ; and this only twenty minutes after its eyes had 
been allowed to see the light and the first time it had ever 
moved its legs. A young chicken, ten minutes after its eyes 
had been unveiled for the first time, seized and swallowed 
a fly at the first stroke.t 
In subsequent papers Mr. Spalding showed that young 
swallows could fly well and avoid obstacles on the first 
attempt ; that young pigs a few minutes old could hear and 
run to their mother, though out of sight ; and that most young 
animals give indications of fear at the voice or presence of 
their natural enemies. 
But in all these cases we have comparatively simple motions 
or acts induced by feelings of liking or disliking ; and we can 
see that they may be due to definite nervous and muscular 
co-ordinations which are essential to the existence of the 
species. That a chicken should feel pleasure at the sound of a 
hen’s voice and pain or fear at that of a hawk, and should 
move towards the one and away from the other, is a fact of 
the same nature as the liking of an infant for milk and its 
dislike of beer with the motion of the head towards the one 
and away from the other when offered to it. But when, at a 
much later period, with all its senses and powers of motion 
fully developed by use and exercise, and with the results of 
the experiences of a year’s eventful life, the bird proceeds to 
perform the highly complex operation of building a nest, we 
have no right to assume without direct proof that it will 
be guided throughout by instinct alone ; and we have seen 
that not only is there no evidence to support this theory, but 
that all the facts we possess are directly opposed to it. 
Since this essay was published, however, some amount of 
1 “On Instinct.” Paper read at British Association, sect. D.,1872; Nature, 
vol. vi. p. 485. 
