336 THE STRUCTURE AND LIFE OF BIRDS. cuap. 
be ,inborn, only requiring to be awakened, or, as 
Professor Morgan says, requiring “only the touch of 
the trigger to fire off the complicated train of activities, 
the ability to perform which is innate.’ The Razor- 
bill affords a good illustration ; he is a born diver, and 
yet cries plaintively when his mother coaxes him to 
take the first plunge. The principle will become clear 
if we imagine an attempt to teach a bird to build 
anything but its own particular nest, to imitate the 
Bower Bird, for instance, and construct an elaborate 
arbour, or an attempt to teach the Chaffinch to build a 
domed nest like the Long-tailed Tit’s, or a House- 
Sparrow or a Wood-pigeon to build a neat nest of any 
kind. If it were ever successful it would at any rate 
require much time, whereas just a hint, if even that 
is required, is enough to set a bird off building as its 
parents have built before it. Any one who has taught 
boys must have noticed what is not very dissimilar. 
A boy—some vara avis—will perhaps master Euclid as 
if geometry were born in him. In classics much 
teaching, and much work on his part may produce 
very little result. In short, all faculties are innate, 
and, supposing them to exist, the only question is, 
whether it requires any teaching or practice, and if 
so, how much, to awaken them. 
Birds have, compared with man, very few and very 
limited powers, and they differ from us, besides, in this, 
that it requires comparatively very little stimulus to 
bring their faculties into full working order. A few 
suggestions from an older bird on a particular subject, 
and a younger one at once advances the greater part 
of the way towards the furthest point to which his 
