35^ The Bird 



specialized type of foot which is adapted to cHmbing or 

 to swimming, so that any classification based on such 

 similarity of locomotion is obviously false. 



From the tiny limbs of a hummingbird to the gigantic 

 shanks of an ostrich, the legs of birds, with a very few 

 exceptions, are covered with scales, most emphatic re- 

 minders of the reptilian ancestry of both these extreme 

 forms of feathered life. The real foot of a bird, as the 

 term is used in speaking of other animals, extends to the 

 backward-bending joint, or heel. Part of the lower leg 



Fig. 285.— Foot of Raven. 



is thus concealed by the feathers and skin, while the upper 

 leg, or thigh, is generally wholly within the body, as we 

 saw in the chapter treating of the framework. 



As before, we must call on the crow, in many respects 

 standing very near the top of the scale of bird life, yet 

 which has found it good to hold to the typical bird's foot. 

 And indeed it serves him well, for with it he can walk on 

 snow or ice; wade in shallow water; perch in trees; scratch 

 or claw the ground and hold down a crab's carapace, 

 while he extracts the edible portion. Not only this, but 

 he can hop like a sparrow or walk like a lark at will. 



