CHAPTER XIV 
FEET AND LEGS 
MARRIED far and wide by the power of flight, 
no two species of birds have exactly similar 
environments. When the wings cease their la- 
bour and are folded close to the sides, the bird must depend 
upon its feet to carry it to its food and to keep it out of 
danger, whether its footing be in a tree-top or on a cliff; 
in shallow water or on the deep; in mud, sand, or snow. 
Thus we realize the need for many varied adaptations 
in the way of feet and legs. 
Although birds are descended from five-toed ancestors, 
yet no living wild bird, and none of those which we know 
only as fossils, has more than four toes on each foot. The 
disposition of these toes—four, three, or two, as the 
case may be—is always in accordance with the habits of 
the bird. 
The most common type of avian foot is that in which 
the arrangement is of three toes in front, with the fourth, 
corresponding to our great toe, pointing backward. This 
was the arrangement in our first bird, the Archeopteryz, 
and for perching birds, as well as for many others with 
very different habits, it has stood the test of six millions 
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