346 Animal Lite 
we shall find that reason improves on this. A very young plover or teal will 
squat until it is picked up. Later it will only do so until reason tells it that it is 
seen, when it instantly stops the instinctive act, and acts according to the suggestions 
of reason. Half-grown leverets will squat till you pick them up. Notso, as a rule, 
the full-grown hare. Instinctive actions among birds are perhaps less common than 
is believed; or rather, what appear to be instinctive actions are in some cases due 
to a change of physical condition. 
Incubation, a very trying process, one would imagine, to such active creatures 
as birds, is no doubt the result of instinct. But very soon it proceeds, not from 
an instinctive impulse, but as the result of a peculiar physical state, almost like the 
results of coma, or of the administration of ether, or alcohol, or anything else which 
for the time alters the working of mind and body. When a hen becomes “broody ” 
she very soon is quite imsane about everything else, and can be handled and picked 
up; neither will she cease to sit, even though the eggs are taken from her. This is 
perhaps the closest imstance among higher animals of an approach to the automatic 
instinct of insects. But it takes a little time before the hen passes into this state, 
which is, moreover, probably more strongly marked in the fowl and game birds than 
in some others. A hen partridge, if disturbed during the first twenty-four hours in 
which she is sitting, will often desert. She is not yet thoroughly “broody.” But 
three days later, if put off her eggs she will often cluck about close by like a 
broody hen. 
A swan, though it has the instinct to sit, never loses her sense as does a fowl, but 
actively aids her instinct by reasonable actions. While on the nest she stretches 
round her long neck, and all day long and every day keeps adding to the nest any 
material she can reach. 
She also carefully turns her eggs once or twice a day with her bill; yet her 
reasoning powers are curiously limited. She will do all this, and carry her young on 
her back on the water; yet if a cygnet fall out of the nest during the first day of 
hatching, it never occurs to her to pick it up and put it under her. 
Nest-building by birds is a border-line action. They inherit the instinct to build, 
and the knowledge of one or more particular classes of design. Yet the site, material, 
and workmanship are very largely matters of reason and choice. What guides birds 
when migrating, and the sources of their remembrance of places, still remain absolutely 
unknown to us. Among the higher mammals these acts appear as manifestations of 
something excelling instinct; yet it may prove that they are border-line actions also, in 
which the mrnd of birds, which is highly developed, uses instinct as material, and so 
forms conclusions of which we can only see the astonishing results. 
In the case of the beaver, which constructs an elaborate engineering device in the 
form of the dam, which keeps the water opposite its burrow or “lodge” at a uniform 
depth, every act, from the cutting down of trees to the formation of the dam on proper 
principles of construction, is done by a reasoning process of a very high order. Yet 
we must assume that all these processes of reason are subsidiary to a “fixed idea,” 
implanted entirely by instinct, that it must make a dam, a notion which is ready-made 
in the brain of every beaver which is born. 
Can we at all detect the nature of the dividing line between the instinctive and 
the rational by our own experience? The answer is, probably not. By the fact that 
we are the most rational creatures, we are also the least instinctive; and what little 
primary instinct we had is improved away. We have not enough of it left for us 
to try experiments with. We cannot trace the survival of instinctive or automatic acts 
even in primitive races, for the more closely they are examined the less instinctive do 
they appear. Even the well-known power of savages to find their way turns out to 
