Birds Feet and Legs Strongly in Evidence 135 



quoting. ' ' Most small birds " he says ' ' hop ; but wag- 

 tails and larks walk, moving their legs alternately ; all 

 the duck kind waddle ; divers and auks walk as if fettered, 

 and stand erect on their tails ; crows and daws swagger 

 in their walk ; woodpeckers use their tails, which incline 

 downward, as a support when they run up trees ; parrots, 

 like all other hook-clawed birds, walk awkwardly, and 

 make use of their bills as a third foot, climbing and de- 

 scending with ridiculous caution. All the poultry 

 (Gallina) parade and walk gracefully and run nimbly." 



It is worthy of remark that, as the bones commonly 

 considered as belonging to the leg in bird correspond 

 to the heel of the human foot, all birds must walk, as we 

 may say, on tiptoe. As they have their centre of gravity, 

 however, not directly over their legs, but more forward, 

 it requires peculiar contrivances in their formation to 

 enable them to balance themselves on their toes. Accord- 

 ingly, birds have their toes for the most part propor- 

 tionately much longer than other animals, while the 

 great flexion of the leg upon the thigh brings the toes 

 more under the centre of gravity. 



Birds have also this further peculiarity, that the stand- 

 ing posture is their state of most perfect rest, arising from 

 the structure of their legs, as first explained by the old 

 Italian naturalist, Borelli. The tendons of the muscles 

 which bend the claws pass over the joints of the heel and 

 are joined there by another muscle which passes over the 

 knee, so that the bending of the heel is necessarily followed 

 by a bending of the toes. When a bird, therefore, alights 

 on the branch of a tree, the weight of its body bends those 

 joints, and thus puts the tendons on the stretch, which 

 draws in the claws to lay hold of the branch without any 

 seeming effort on the part of the bird. 



