272 



BIRDS 



'Jhigh 



arm cannot assume because our hand has not so much 

 freedom of movement at the wrist. The long feathers that 

 grow upon the end portion, or hand of the wing, are called 

 the primaries and those on the forearm the secondaries. 



The wings are attached to the dorsai side of the body so 

 that the weight of the latter will be suspended from the 

 point of support when the bird is flying. 



Legs and feet. — The legs of the sparrow are slender and 

 short, for they are not much used as organs of locomotion. 

 Sparrows hop rather than walk and long 

 legs are not needed. Like the wings, the 

 legs are attached well toward the dorsal 

 side of the animal so that the weight is 

 suspended from the point of support. This 

 f/Shanh is of advantage to an animal that is obhged 

 to reach the ground for all of its food. 

 The hip joints act as pivots on which the 

 body swings between the legs. 



Each leg consists of three parts : thigh, 

 shank, and foot (Fig. 186). The foot is 

 made up of the four toes and the ankle 

 Fig. 186.— Bones which is the scaly part of the leg not 

 of sparrow's leg. govered by feathers. Each toe is com- 

 posed of several segments and ends with a claw. 



Perchmg. — The sparrow belongs to the perching birds. 

 Whenever the feet of the sparrow are placed on a support 

 and the body lowered, the toes will automatically close and 

 grasp the perch. A tendon running from the toes passes 

 up the leg in such a way that whenever the leg is bent, the 

 tendon is pulled so strongly that the toes are curved about 

 the support. The closer the body gets to the support, the 

 more firmly will the toes grasp it. Therefore, the sounder 



\Foot 



