408 



BIRD. 



Before taking leave of tliis branch of the subject 

 we may further remark, that there are three muscles 

 on each side of the keel of the sternum, in all flying 

 birds ; and that the principal action of the wing in 

 flight is produced by those muscles. There is an 

 advantage in this arrangement ; and so also is there 

 an advantage in that arrangement in the legs of birds, 

 by which the muscles of these- arc placed near the 

 body, and the tarsi and part of the tibia: formed chiefly 

 of bone?, tendons, and ligaments. By the arrange- 

 ment in the wings, the wing itself is rendered lighter 

 than if muscles had been distributed over its whole 

 length, to any greater extent than is necessary for 

 stretching and bending the local joints. Not only 

 this, but the circulation of blood necessary for the 

 support of much muscular energy, and the supply of 

 the waste which that would occasion, could not be 

 carried on without an extraordinary propelling power, 

 in organs which move so rapidly as the extremities of 

 the wings. Here, again, we may perceive a remark- 

 able coincidence of advantages. That structure of 

 the wing which adapts it best for being an organ of 

 support and progressive motion jointly in the air, is 

 also the one which renders it, the most easily move- 

 able and the most easily nourished, so that the labour, 

 whether mechanical in the muscles, or physiological 

 in the energy of life by which the muscles are worked, 

 is always the least possible in proportion to the motion 

 produced ; and thus while every bird has enough and 

 to spare of energy for the average; performance of 

 those functions required for its place in nature, it 

 is at the same time an instance of the most perfect 

 economy in the whole of its furnishings and arrange- 

 ments. 



Of the three mnscles on each side of the sternum, 

 by far the largest one is that which depresses the 

 wing. It is called the great pectoral mu>cle ; and, in 

 birds of powerful flight, those two muscles are heavier, 

 or contain more substance than all the other muscles 

 in the body. The second muscles raise the wings, 

 and prevent them from turning on edge, which neither 

 <jf the other muscles could do without impeding the 

 freedom of their proper motion in working the wing 

 upwards and downwards at right angles to the axis of 

 the body. There is, however, a slight oblique motion 

 in the elbow joint of the wing, by means of which 

 this third or central muscle causes it to strike partially 

 forwards, at the same time that the great pectoral 

 muscle makes it strike downwards. 



Such are some of the motions of the more efficient 

 wings of birds, and such some of the instruments by 

 which they are performed ; but from the jer falcon, in 

 which they are the most perfectly developed and the 

 most in accordance with the whole skeleton and other 

 structure, and therefore form, along with the most 

 predatory claws and beak, and the digestive organs 

 the best adapted for subsistence upon recent flesh, 

 the most direct means of arriving at the habit and 

 character there is a gradual decline of the efficiency 

 of the wings, as compared with the other active struc- 

 tures, until we come to the ostrich, which has only a 

 sort of rudi mental flaps to steady it as it runs, the 

 penguin, whose rudimental wings seem to answer 

 only the same purpose in swimming, or the apteryx, 

 whose wings are covered by the skin, thatched by the 

 feathers, and seem to answer no purpose whatever. 

 But though there is this gradation, and though in as 

 far ns the wings, and all those parts of the skeleton, 

 and tiie muscles which are connected with the wings, 



are concerned, we can trace it with comparative! v 

 little difficulty, yet it is so far from taking the fcab'lt 

 of the bird along with it in any other respect than 

 that of mere tlight, that one pair of wings carry us 

 to the sea, a similar pair to the forest or the plain, 

 and a pair still similar to the cliff of the mountain. 

 Nor are the purposes for which the wings carry the 

 birds, and also us in the study of them, less varied 

 than the places, wings very similar to each other, act 

 to capture warm-blooded animals, insects, fishes, ber- 

 ries, seed?, and BO endless a variety of substances, 

 that we are compelled to examine the other charac- 

 ters of the bird before we can arrive at any certain 

 conclusion respecting the office which it performs in 

 nature, or the use to which it may be applied in art. 

 We are not, however, to attempt making a classifica- 

 tion of birds, but to explain the principles of one which 

 is already made ; and therefore the shortest as well as 

 the simplest course would be, first, to mention the 

 classification, and then to point, out those peculiarities 

 in the three grand actions of birds, and their 

 requisite organisations, upon which that classification 

 is founded. 



IV. CLASSIFICATION OF BTRDS. In this we shall, 

 as already said, adopt chiefly the arrangement of 

 Cuvier, not that it is perfect, or even free from objec- 

 tion in all its parts, but because the well-earned 

 celebrity of its author has given it a stability in the 

 general opinion of mankind, the overturning of which 

 would require much knowledge and more hardihood; 

 and be, till more knowledge is obtained, after all a 

 work of supererogation, except in some of the details. 



Cuvier divides the whole class into five orders, 

 Birds of prey ( ACCIPITRES) ; sparrow-like, or hopping 

 birds (PASSEKES); climbing birds (SCANSOI-.ES) ; 

 poultry birds (GALLINID^) ; running and wading 

 birds (GRALLIDJE) ; and web-footed birds (PALMI- 

 PEDES). This certainly has the advantage of that 

 simplicity of which it partakes in common with other 

 artificial systems of the works of nature, that the first 

 step in the knowledge of it is very easily taken. But 

 it has, at the same time, all the counterbalancing dis- 

 advantages. It does not simplify the knowledge of 

 birds ; it is only simple because it conveys very 

 little knowledge. When we come to grapple with 

 the real knowledge, we must go to more minute 

 divisions, and encounter much more labour; but even 

 thus much is a beginning, and may prove an incentive 

 to some, though it may also lead others to be content 

 with the shadow without the substance, as has been 

 remarkably the case with the Linnaean artificial sys- 

 tem of Botany. 



The characters of these orders, as well as of the 

 tribes or families into which they are divided, and 

 the genera and species of which they are made up, 

 will be found under their respective names. in the 

 order of the alphabet, and therefore we need not here 

 enter into the particulars. But, as we cannot show 

 the connexion which there is between the three great 

 systems, to which the bills, the wings, and the feet, 

 are, as it were, the keys, without some notice of the 

 general characters on which the orders are founded, 

 or at least their fitness for being such a foundation, 

 we must devote a few words to each. 



ACCIPITRES. This order is the most natural in 

 the system, and it is so, because it is founded not upon 

 a single character, but upon the general habit of the 

 birds, in the formation of which all their leading 

 organisations bear a part. The distinctions of the 



