THE BIRD: ITS PARTS, VOICE, AND COLOR 255 
THE LEcGs 
Use. — There is a great and interesting difference in the 
use which birds make of their legs. The domestic hen uses 
hers for walking, running, scratching, and roosting. They 
are well developed and strong. The Chimney Swift never 
uses its legs except at night for clinging, by the aid of the tail, 
to some vertical surface. They are therefore small and 
weak. The majority of our smaller perching birds hop or 
jump instead of walk, while the other land birds and all the 
water birds walk, and do not ordinarily hop. _ 
Structure. — In structure the leg of a bird is similar to the 
hind leg of a horse. The heel or hock is about the middle of 
the part of the leg that we see, the lower leg corresponds to 
the human foot, and the hoof to the toes. The knee is brought 
up close to the body and covered by the body skin, thus 
apparently making a part of the body the portion that corre- 
sponds to the thigh in human anatomy. In the bird all this 
is the same except that it has toes instead of hoof. The part 
above the heel, the “ drum stick,”’ is usually well covered with 
feathers, so that the principal part we see is the naked joint 
below the heel. This is called the tarsus. Sometimes, as in 
most Owls and Grouse, the tarsus also is feathered. 
Tue FEET 
Number and Arrangement of Toes. —'The usual number of 
toes is four; but one of them, the hind toe, is often much 
shorter than the rest, and in some species it is entirely want- 
ing, thus leaving only three. When there are four toes, the 
most common arrangement is to have three in front and one 
behind, as we see in the Sparrows. Another arrangement 
gives two in front and two behind, as in Woodpeckers and 
