And such
instances do occur in nature. Can a more striking instance of
adaptation be given than that of a woodpecker for climbing trees and
for seizing insects in the chinks of the bark? Yet in North America
there are woodpeckers which 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.
Pages:
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231