tributed to her sense of smell; she, detecting the presence
of an enemy by the scent of his hand left behind in the nest, recognizes
the danger, and therefore abandons the nest. But numerous experiments
along this line teach me that smell has nothing to do with it whatever.
I have removed eggs with a long iron ladle, the bowl of which I had
carefully refrained from touching, and also with sticks freshly cut in
the wood, and yet the birds would invariably abandon their nests. On the
contrary, when all, or nearly all, the eggs have been laid, several may
be removed either with the ladle or with the naked hand, and yet the
bird will not abandon her nest. She seems to be able to count up to six
or eight; beyond this latter number her faculty of computing does not
extend. After the full laying has been deposited in the nest and the
process of incubation has become established, a large number of the eggs
may be removed, and yet the bird will continue to set until the
remaining eggs have been hatched out.

The faculty of computing seems to be present in other birds to some
extent; the domesticated guinea-fowl and the turkey sometimes possess it
in a marked degree, though in most of these fowls domestication has
almost entirely eradicated it. The domestic barnyard hen has had her
nest robbed for such a long period of time that she has lost the faculty
of counting. But even this meek provider of food for mankind is able, in
some instances, to count one: she will not lay in her nest unless a
nest-egg be left to delude her. The nest-egg may be wholly factitious
and made of china, marble, chalk, stone or iron painted white; the hen
does not seem to care so long as it bears some resemblance to an egg.

That the turkey-hen can count, the following instance occurring under
my own observation would seem to indicate. The bird had a nest in my
garden in which she had deposited three eggs. One day another turkey,
seized with a desire of ovipositing, spied this nest and laid an egg
therein. The original owner of the nest came along soon after the
interloper had left her egg; she examined the nest carefully, and turned
the eggs with her beak. Finally she thrust her beak through the shell of
an egg and bore it far from the nest before dropping it on the ground.
Now, as far as I could tell, the eggs were alike, but the sharper and
more discriminating eyes of the turkey undoubtedly saw, on close
examination, some peculiarity in color or shape