when she is alarmed gives quite a different call
from when she is happy and flying about. She has a
particular call when she has young ones about. So
that those who have watched and listened and know
her call when they hear it know pretty well where
the young ones are or where the nest is and so on.

"_How to Hide Yourself._--When you want to observe
wild animals you have to stalk them, that is,
creep up to them without their seeing or smelling
you.

"A hunter when he is stalking wild animals keeps
himself entirely hidden, so does the war scout
when watching or looking for the enemy; a
policemen does not catch pickpockets by standing
about in uniform watching for them; he dresses
like one of the crowd, and as often as not gazes
into a shop window and sees all that goes on
behind him reflected as if in a looking-glass.

"If a guilty person finds himself being watched,
it puts him on his guard, while an innocent person
becomes annoyed. So, when you are observing
people, don't do so by openly staring at them, but
notice the details you want to at one glance or
two, and if you want to study them more, walk
behind them; you can learn just as much from a
back view, in fact more than you can from a front
view, and, unless they are scouts and look around
frequently, they do not know that you are
observing them.

"War scouts and hunters stalking game always carry
out two important things when they don't want to
be seen."

One is _Background_.--They _take care that the
ground behind them, or trees, or buildings, etc.,
are of the same colour as their clothes_.

And the other is "_Freezing_".--If an enemy or a
deer is seen looking for them, _they remain
perfectly still without moving so long as he is
there_.

_Tracking._--The native hunters in most wild
countries follow their game by watching for tracks
on the ground, and they become so expert at seeing
the slightest sign of a footmark on the ground
that they can follow up their prey when an
ordinary civilized man can see no sign wha