390 



B I H D. 



The posterior extremities, or feet, of birds, are 

 their chief organs of progressive motion, and their 

 chief supports when at rest, upon the ground or 

 other solids. But the feet perform more operations 

 than the wings. In some birds they are used for 

 clutching or killing prey ; in others for scraping in 

 the ground for food, and also in the digging of bur- 

 rows and the preparation of other places for the depo- 

 siting of the eggs ; in others, again, they are used as 

 a sort of hands in climbing, in which operation they 

 are in some species assisted by the bill; and in others 

 still they are occasionally used in conveying the food 

 to the month, or in holding it while it is preparing 

 for swallowing, by the action of the bill. They are 

 also varied to suit the kinds of surfaces which are 

 frequented by the different tribes ; and they serve as 

 stilts for wading, and as paddles or oars for acting in 

 the water. The general characters of the foot and 

 leg of a bird are so well preserved through all their 

 almost innumerable varieties of form, that there is no 

 danger of mistaking them for the feet of any other 

 class. The feet of some of the reptiles resemble 

 them the most ; but still the shapp, the articulations, 

 and the covering, even in the purl of the bird which 

 is not feathered, are all or each sulficient for distin- 

 guishing the one from the other. 



The feet of birds are the organs of one of their 

 most important motions ; and thus they are made 

 one of the grounds of that very imperfect classifi- 

 cation which science has been enabled to make of the 

 feathered race. As the bill is a sort of guide to the 

 species of food ; and the wings to the kind, style, and 

 partially the purpose of flight ; so the feet are a sort 

 of guides to the home and habitation of the bird, and 

 also to the place of its feeding, if its habit be not to 

 feed on the wing; and whether that is its habit or 

 not, can, in some degree, be determined by the 

 characters of the wings and the bill. Birds which 

 habitually feed on the wing have, in general, pointed 

 wings, and can wheel and turn on the tips ol them, 

 whatever may be their other characters ; and they 

 have generally either a wide gape or a powerful and 

 rapid action of the mandible, so as to catch their 

 prey by snapping. 



The leg and foot always consist of three princi- 

 pal jiioccs, independently of the toes : the femur or the 

 thigh-bone, the tibia or leg-bone, and the tarsus or 

 foot-bone. The tarsus, like the bones of the wings, 

 answering to the palm of the hand, is always very 

 much elongated; and it is popularly called the leg, 

 though in fact it is the foot. Birds, in general, follow 

 the same law as the mammalia in the use of their 

 posterior extremities as organs of walking; they are 

 digitigrade, or walk upon the toes, and not on the 

 tarsus; and those which walk upon the latter have 

 even a more awkward and shambling gait than the 

 mammalia which have that habit ; and indeed they 

 can hardly be said to walk at all. The knee joint, 

 or articulation of the tibia with the femur, which 

 bends forward only, appears to be inadequate to the 

 balancing even of a nearly inflexible spine in any but 

 a nearly vertical position. In man we have a flexible 

 spine, balanced with the whole length of the tarsus 

 on the ground, but it is in an erect position ; and 

 besides there is' the astragalus or heel-bone in man, 

 which riot only sustains tlu: balance of the foot, but 

 gives a lever power to the tendo Achillis, which, when 

 pulled by the strong muscles to which it is attached, 

 throws the pressure of the body upon the balls of the 



toes. The human foot is not, however, a nt subject 

 of comparison with the feet either of birds or of the 

 mammalia. See the articles BIMANA and MAN. 



Those birds which bring the whole length of the 

 tarsus to the ground when they walk, or attempt to 

 walk, are but few in number ; and they are all aquatic 

 birds, the proper functions of whose feet is sw imming 

 and not walking. Their legs are articulated fur 

 backward, and they have that oblique motion of the 

 joints for throwing the swimming feet at some dis- 

 tance from the body of which some notice will be 

 found in the article BEAVEK. They spend most of 

 their time, and rind the whole or nearly the whole of 

 their food, in the water; and such of them as have 

 not the power of Might (for some of them are so ex- 

 clusively aquatic that they can neither fly in the air 

 nor walk on the earth) deposit their eggs near the 

 margin of the water, so that their terrestrial opera- 

 tions are limited to shuffling along a few feet, or 

 sitting erect upon the rocks, in which latter, and even 

 in the former, the tail assists in supporting them, as is 

 the case with beavers when they stand up. 



The head of the femur is articulated rather farther 

 forward in walking birds than in the mammalia; 

 and the femur itself is not so free or so much used 

 in the motion of the leg. The tibia, or true leg, is 

 the part usually called the thigh, or in the larger 

 birds, which are brought to table, the drum-stick. 

 In birds which make much use of their feet, the tibia 

 is much loaded with muscles ; and it is generally 

 protected by a profusion of soft and downy feathers, 

 especially in those birds which are much exposed to 

 the weather, and use their toes in clutching or killing 

 their prey. 



Many of the wading birds, and some of the running 

 ones, have a portion of the under end of the tibia 

 bare of feathers ; but the muscles do not descend so 

 low as that part ; and it may be considered as a 

 general arrangement in the structure of birds that the 

 muscles are always under a protecting covering of 

 feathers. 



The tarsi and toes, and also the naked portions of 

 the tibia, contain few or no muscles, but are made up 

 of bones, tendons, straps of ligaments for keeping 

 the tendons in their places, and the integuments, 

 which are very firm and tough skin, variously covered 

 with scales, sometimes imbricated and sometimes 

 reticulated ; and there are often pads on the under 

 part of a consistency not very unlike caoutchouc, or 

 Indian rubber, and nearly as elastic and as difficult 

 to wet as that substance. 



The toes on the foot, three before and one behind, 

 may be regarded as the normal number in the order; 

 but, they are fewer in some of the running birds, and 

 more numerous in some of the other orders. The 

 toes, however, vary so much in the manner of their 

 articulation, in their si/e and power, and in their ap- 

 pendages, that they do not admit of general descrip- 

 tion. The toes are the portion of the foot usually 

 taken as the ground of systematic arrangement; 

 though as the principal muscles which move the toes 

 aie not in the toes themselves, or even in the tarsus, 

 the whole leg would be a better indication of the 

 habits of the bird; though, being a more complicated 

 structure, an arrangement founded upon it would 

 make the elements of the system apparently a little 

 more difficult. But the difficulty would be apparent 

 and not real ; and it is very probable that, if we 

 included a little more character, and thereby gave a 



