comes on them; but, if the deadliest enemy approaches with slow caution,
as snakes do--and snakes must be very ancient enemies to birds--there is
no fear or suspicion shown, even when the enemy is in full view and
about to strike. This, it will be understood, is when no warning-cry is
uttered by the parent bird. This shrinking, and, in some cases, hiding
from an object corning swiftly towards them, is the "wildness_"_ of
young birds, which, Darwin says again, is greater in wild than in
domestic species. Of the extreme tameness of the young rhea I have
already spoken; I have also observed young tinamous, plovers, coots,
&c., hatched by fowls, and found them as incapable of distinguishing
friend from foe as the young of domestic birds. The only difference
between the young of wild and tame is that the former are, as a rule,
much more sprightly and active. But there are many exceptions; and if
this greater alertness and activity is what is meant by "wildness," then
the young of some wild birds--rhea, crested screamer, &c.--are actually
much tamer than our newly-hatched chickens and ducklings.

To return to what may be seen in nestling birds, n very young, and
before their education has begun, if quietly approached and touched,
they open their bills and take food as readily from a man as from the
parent bird. But if while being thus fed the parent returns and emits
the warning note, they instantly cease their hunger-cries, close their
gaping mouths, and crouch down frightened in the nest. This fear caused
by the parent bird's warning note begins to manifest itself even before
the young are hatched--and my observations on this point refer to
several species in three widely separated orders. When the little
prisoner is hammering at its shell, and uttering its feeble _peep,_ as
if begging to be let out, if the warning note is uttered, even at a
considerable distance, the strokes and complaining instantly cease, and
the chick will then remain quiescent in the shell for a long time, or