sert, and, when first seen after crossing the
colonial boundary, are said often to exceed forty thousand in number. I
can not give an estimate of their numbers, for they appear spread over
a vast expanse of country, and make a quivering motion as they feed, and
move, and toss their graceful horns. They feed chiefly on grass; and as
they come from the north about the time when the grass most abounds,
it can not be want of food that prompts the movement. Nor is it want of
water, for this antelope is one of the most abstemious in that respect.
Their nature prompts them to seek as their favorite haunts level plains
with short grass, where they may be able to watch the approach of an
enemy. The Bakalahari take advantage of this feeling, and burn off large
patches of grass, not only to attract the game by the new crop when it
comes up, but also to form bare spots for the springbuck to range over.

It is not the springbuck alone that manifests this feeling. When oxen
are taken into a country of high grass, they are much more ready to be
startled; their sense of danger is increased by the increased power
of concealment afforded to an enemy by such cover, and they will often
start off in terror at the ill-defined outlines of each other. The
springbuck, possessing this feeling in an intense degree, and being
eminently gregarious, becomes uneasy as the grass of the Kalahari
becomes tall. The vegetation being more sparse in the more arid south,
naturally induces the different herds to turn in that direction. As they
advance and increase in numbers, the pasturage becomes more scarce; it
is still more so the further they go, until they are at last obliged, in
order to obtain the means of subsistence, to cross the Orange River, and
become the pest of the sheep-farmer in a country which contains scarcely
any of their favorite grassy food. If they light on a field of wheat
in their way, an army of locusts could not make a cleaner sweep of the
whole than they will do. It is questionable whether they ever return, as
they have never been seen as a returning body. Many perish from want of
food, the country to which they have migrated being unable to support
them; the rest become scattered over the colony; and in such a
wide country there is no lack of room for all. It is probable that,
notwithstanding the continued destruction by fire-arms, they will
continue long to hold their place.

On crossing the Orange River we come into independent t