topmost foliage, is hunted over by them. The Sclerurus, although an
inhabitant of the darkest forest, and provided with sharply-curved
claws, never seeks its food on trees, but exclusively on the ground,
among the decaying fallen leaves; but, strangely enough, when alarmed it
flies to the trunk of the nearest tree, to which it clings in a vertical
position, and, remaining silent and motionless, escapes observation by
means of its dark protective colour. The Drymornis, a large bird, with
feet and tail like a woodpecker, climbs on tree-trunks to seek its food;
but also possesses the widely-different habit of resorting to the open
plain, especially after a shower, to feed on larvae and earthworms,
extracting them from a depth of three or four inches beneath the surface
with its immense curved probing beak.

Again, when we consider a large number of species of different groups,
we find that there is not with the Tree-creepers, as with most families,
any special habit or manner of life linking them together; but that, on
the contrary, different genera, and, very frequently, different species
belonging to one genus, possess habits peculiarly their own. In other
families, even where the divergence is greatest, what may be taken as
the original or ancestral habit is seldom or never quite obsolete in any
of the members. This we see, for instance, in the woodpeckers, some of
which have acquired the habit of seeking their food exclusively on the
ground in open places, and even of nesting in the banks of streams. Yet
all these wanderers, even those which have been structurally modified in
accordance with their altered way of life, retain the primitive habit of
clinging vertically to the trunks of trees, although the habit has lost
its use. With the tyrant birds--a family showing an extraordinary amount
of variation--it is the same; for the most divergent kinds are
frequently seen reverting to the family habit of perching on an
elevation, from which to make forays after passing insects, returning