feed largely on fruit, and others with elongated wings which chase
insects on the wing; and on the plains of La Plata, where not a tree
grows, there is a woodpecker, which in every essential part of its
organisation, even in its colouring, in the harsh tone of its voice,
and undulatory flight, told me plainly of its close blood-relationship
to our common species; yet it is a woodpecker which never climbs a
tree!
Petrels are the most aerial and oceanic of birds, yet in the quiet
Sounds of Tierra del Fuego, the Puffinuria
berardi, in its general habits, in its astonishing power of diving, its
manner of swimming, and of flying when unwillingly it takes flight,
would be mistaken by any one for an auk or grebe; nevertheless, it is
essentially a petrel, but with many parts of its organisation
profoundly modified. On the other hand, the acutest observer by
examining the dead body of the water-ouzel would never have suspected
its sub-aquatic habits; yet this anomalous member of the strictly
terrestrial thrush family wholly subsists by diving, grasping the
stones with its feet and using its wings under water.
He who believes that each being has been created as we now see it, must
occasionally have felt surprise when he has met with an animal having
habits and structure not at all in agreement. What can be plainer than
that the webbed feet of ducks and geese are formed for swimming? yet
there are upland geese with webbed feet which rarely or never go near
the water; and no one except Audubon has seen the frigate-bird, which
has all its four toes webbed, alight on the surface of the sea. On the
other hand, grebes and coots are eminently aquatic, although their toes
are only bordered by membrane. What seems plainer than that the long
toes of grallatores are formed for walking over swamps and floating
plants, yet the water-hen is nearly as aquatic as the coot; and the
landrail nearly as terrestrial as the quail or partridge. In such
cases, and many others could be given, habits have changed without a
corresponding change of structure. The webbed feet of the upland goose
may be said to have become rudimentary in function, though not in
structure. In the frigate-bird, the deeply-scooped membrane between the
toes shows that structure has begun to change.
He who believes in separate and innumerable acts of creation will say,
that in these cases it has pleased the
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