ADAPTATION OF STRUCTURE TO HABITS. 
283 
slightest inequality in the bark serves as a point d!appui . 
While in the act of climbing, hammering, or chiselling, 
the tail serves as a spring. These labours are performed 
with the assistance of the bill, so wonderfully adapted, 
from its singular wedge-like shape, to these especial 
duties, though seldom or never used to collect food. For 
this last-mentioned duty it is provided with a long round 
tongue, capable of being projected to a great length, and 
furnished with a horny tip, which is again provided with 
small hooks: with this weapon it manages to extract 
insects which he hidden in holes and crannies. The 
Woodpecker seems especially adapted to seek its liveli¬ 
hood from the abundant nourishment afforded amongst 
the cracks, rents, and hollows of the main body and 
limbs of decayed trees. Its beak serves as chisel, and 
its tongue as harpoon, while foot and tail enable it to 
look down with contempt upon all the artifices contrived 
by man to assist him in climbing. 
A step lower conducts us to other members of the 
feathered tribe, who obtain their food from the ground. 
Among these we find some harmless individuals, who, 
according to circumstances, are often obliged to seek 
safety from their enemies in concealment. The colouring 
of their plumage affords them the most ready means of 
escape : these tints always closely resemble the colour of 
the soil, on which they pass the greater portion of their 
lives; and, indeed, in some cases, the one changes exactly 
at the same time and in the same manner as does the 
other. The plumage of most Larks, Pipits, Partridges, 
many Waders and running birds, shows a design and 
colouring eminently corresponding with the localities 
where they are found. The same may be said of most 
of the weaker birds and, indeed, other animals ; but in no 
