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As some degree of variation in instincts under a state of nature, and the inheritance of such variations, are indispensable for the action of natural selection, as many instances as possible ought to
→be here
given; but want of space prevents me. I can only
that instincts certainly do vary— for instance, the migratory instinct, both in extent and direction, and in its total loss. So it is with the nests of birds, which vary partly in dependence on the situations chosen, and on the nature and temperature of the country inhabited, but often from causes wholly unknown to us: Audubon has given several remarkable cases of differences in
of the same species in the northern and southern United States. Why, it has been asked, if instinct be variable, has it not
to the bee "the ability to use some other material when wax was
But what other
could bees use? They will
→with and use,
as I have seen,
hardened with vermilion
softened with lard. Andrew Knight observed that his bees, instead of laboriously collecting propolis, used a cement of wax and turpentine, with which he had covered decorticated trees. It has lately been shown that bees, instead of searching
for
pollen, will gladly use a very different substance,
Fear of any particular enemy is certainly an instinctive quality, as may be seen in nestling birds, though it is strengthened by experience, and by the sight of fear of the same enemy in other animals.
fear of man is slowly acquired, as I have elsewhere shown, by
→various animals
desert islands; and we
see an instance of
even in England, in the greater wildness of all our large birds
→than of
our small birds; for the large birds have been most persecuted by man. We may safely attribute the greater wildness of our large birds to this cause; for in
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