ADAPTATION IN BIRD ANATOMY 



Adaptation is a principle that runs lusty swimmers they have large leg 



through all nature. There is no fact muscles instead. 



more prominent. It is nature's response 'Turning to other parts of the bird an 



to demand, her answer to necessity, abundance of material for our subject 



The large muscle of the blacksmith ; will be found. Just as we are enabled to 



the calloused hand of the laborer and the read on the face of an individual quite 



coiled tendrils of the vine, are very fa- accurately the story of his inner life, so 



miliar examples. But nowhere is the is there expressed — if we will but read — 



principle more conspicuous than in in the modifications of the several parts 



bird anatomy. Birds are .so sensitively of the bird, his habits, character and 



organized, and respond so readily to en- environment. If his birdship would 



vironment, that the finest shades of conceal these secrets it is always neces- 



adaptation are exhibited. It is the pur- sary that he hide his head and feet, 



pose of this article to point out some of and even then his leg, or wing, or tail, 



the most important examples of adapta- may tell it all. 



tion to be found in birds, and to show The feet of those birds that spend 



how a knowledge of these facts may much of their time on .the ground (the 



help us to interpret bird life. Robin, Lark, and domestic fowls for ex- 



In the first place; birds fly, and hence ample) are very large, obviously for the 

 have wings. Though some may choose reason that they are much used. On 

 to contend that they have wings and the other hand, the feet of the Chimney 

 hence fly. However that may be, wings Swift, which are practically never used, 

 alone are not sufficient for flight. A for these birds do not perch except on 

 little examination reveals the fact that the nest, are very small — in fact all but 

 the bones of birds are hollow through wanting. The Night-hawk, whose habits 

 which warm air circulates, evidently to are very similar, has legs to small to 

 give the bird buoyancy and render support the body, so instead of perching 

 flight more easy. An exception which crosswise of the limb as most birds do, 

 is additional proof of the principle of rests the body on the limb parellel to it. 

 adaptation is the more solid bones of the This brings to our mind that oft re- 

 ostrich and domestic fowls, which do not peated law of nature : "If you do not use 

 fly. Furthermore, it is found that the you lose," which, however, is merely 

 feathers stand out on the body of the an expression of one side of this princi- 

 bird in such a way as to displace con- pie of adaptation. 



siderable air, which to no small degree It will be observed that those birds 

 enhances the bird's power of flight. By that perch a great deal have well de- 

 removing the feathers from the body of veloped claws, while the Kildeer, a bird 

 the bird, leaving the wings entire, flight that never perches, has no claws at all 

 becomes very awkward and difficult, and to speak of. The same is wanting in 

 in some cases is practically destroyed. Grebes and other water birds. Birds of 



The keel-like form of the body is es- prey have strong, sharp claws; the rea- 



pecially adapted for flight, and the large son is very evident, 



wing muscles of the breast account for The number, position, and relative 



the untiring ease with which some exer- size of the toes of birds is a very large 



cise this power. Birds with remarkable and interesting study in itself. As a 



power of flight have these wing muscles rule birds have four toes, three of which 



very highly developed ; while in birds point forward, the other backward — 



like the grebe, which fly but little these all on a level. But there are many vari- 



muscles are almost wanting; but being ations from this rule. The hind toe of 



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