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STUDY OF ORNITHOLOGY,
ON SCIENTIFIC PRINCIPLES.
The science of ornithology is confessedly one of the most interesting departments of the animal kingdom, and possesses many claims upon the attention of every devout examiner of the works of the Great Creator, as well as of the general observer of nature. In whatever point the feathered tribes are regarded, whether as it respects the place they occupy in the general economy of creation, their instincts, and their habits, or as it respects their almost endless diversity, their varied forms, passing like graduated links from group to group, we are constrained to express our admiration and delight. How beautifully are they adapted for the natural station they occupy, for their instinctive habits, for filling the part allotted by the all-wise Creator! Tenants of the upper air, unlike the mammalia, from whose number the bat alone presumes to invade their realms, they soar above the earth, above its mountains and its vales; they cleave the blue sky, borne up on rapid wings, and thus transport themselves from place to place, or from one country to another, with ease and safety. Familiar with the storm, they rise till lost among the clouds ; and, from their aerial pinnacle, look down upon the outspread earth, lying like a map beneath. Yet are they not confined to the realms of air alone; the earth and the waters are theirs also : some
traverse the fields, some troop around the abodes of man, some dive and sport on the billows of the ocean, some wade the treacherous morass, some scour the desert fearless of the “steed and his rider,” some live among the forest branches, or the umbrageous shade of the sequestered thicket; as for the stork, the fir-trees are her house.”
Nor are they less remarkable for other characteristics of attraction. Some delight by their majestic presence: look at the eagle, proudly resting on the naked cliff; what dignity in his attitude, as, motionless like a statue, his glossy brown plumage all arranged with the nicest care, he surveys the distant prospect, while the fire of his glistening eye betrays his innate ferocity and impetuous daring ; his mate is on her eyry, “she dwelleth and abideth on the rock, upon the crag of the rock, and the strong place. From thence she seeketh the prey, and her
eyes behold afar off. Her young ones also suck up blood; and where the slain are, there is she.” Job xxxix.
Others please us with their gorgeous beauty. Who can look upon the peacock with his plumes of azure, green, and gold, spread out to the bright rays of the sun, and not acknowledge the glory of the spectacle? Others charm our ears with melody, and fill the groves and woodlands with their song. Their melodious songs excite us to praise their and our Creator, and as they ascend upwards they seem to teach us to soar above this world, and to enforce the lesson, your
affection on things above —where Christ sitteth on the right hand of God—not on things on the earth.” Col. iii. 1, 2. Others interest by their familiarity and confidence, their smart and lively actions.
“ The redbreast
pays to trusted man His annual visit. Half afraid he first Against the window beats; then brisk alights On the warm hearth; then, bopping o'er the floor, Eyes all the smiling family askance, And pecks, and starts, and wonders where he is : Till more familiar grown, the table crumbs Attract his slender feet.”
Such are a few of the points of attraction which this race possesses : without expatiating further upon them, we shall advance at once to our subject.
In a work on mammalia, the study of which is necessarily an introduction to that of every other department of Natural History, it was observed (see p. 10) that Cuvier divided the animal kingdom into four great groups or sections, the first of which is that including all vertebrate animals (animalia vertebrata), distinguished by
internal osseous frame-work or skeleton, which affords solidity and support. Their body is composed of a head, trunk, and limbs ; the head consists of the skull, which encloses and protects the brain ; and of the face, which embraces the organs of taste, smell, sight, and hearing. The head rests upon, or is attached to the vertebral column, which is composed of a number of bones moveable one on another, and forming a canal for the medulla oblongata, or spinal marrow. The limbs never exceed four, and are in pairs; but sometimes one pair is wanting, sometimes both. The blood is always red.”—Of this extensive section, divided into four classes, the second is that of Birds, or the class Aves, the subject of our present investigation.
Birds agree with the preceding class, mammalia, in breathing air, in having a double heart, and consequently a systemic and pulmonic circulation *, and in having the blood warm as well as red, that is, of a temperature considerably higher than that of the surrounding medium ; whereas in the two remaining classes, namely Reptiles and Fishes, it is cold, or of a temperature merely equal to that of the surrounding medium. But birds differ from mammalia in one essential particular, namely in being oviparous; that is, instead of producing their young full formed, as do the mammalia, they lay eggs covered with a hard calcareous shell, which contain the embryo, requiring a certain degree of warmth for its
* That is, a circulation of blood through the general system, conducted by one set of vessels arising from the left ventricle, and a circulation the lungs, conducted by another set arising from the right ventricle.
future developement, which being duly applied (and this is generally effected by the assiduous parent brooding on her nest), the young burst at length from their imprisonment, and commence a new existence.
But besides this essential ground of distinction, birds differ from mammalia in having the body covered with feathers, and in the anterior extremities being organs of flight alone. The aggregate of feathers which clothe a bird are termed its plumage, and this in its endless modifications is intimately connected with the habits and manners of the species. Hence it is that these variations are ever studied by the naturalist, not only as evidences of consummate design, but as an index of habits, and even as a clue to natural arrangement. It is easy to perceive that the plumage and habits of the feathered race have an intimate connexion, and that there must consequently be an according modification of the whole system. Look at the wavy plumes which form the wingfeathers of the ostrich: these, beautiful as they are, are the mere mockery of wings, they cannot raise their possessor to the “middle sky;" nor is it designed that they should. Its home is the desert, which it traverses with the speed of the wind; and its limbs resemble those of a horse for strength and muscle. But let us look at a bird expressly formed for rapid flight: we see its feathers close and rigid, often with a burnished metal-like surface; the wings long and pointed, the quill-feathers having acute abrupt edges and strong elastic shafts, and the tail broad, or forked, and equally firm and elastic: such, for example, is the plumage of the humming-bird, a bird which the eye can scarcely follow as it darts by like a flashing meteor. Look again at the bird of buoyant wing, of noiseless flight, the twilight prowler of the fields and woods : its plumage is full, loose, and delicately soft, offering no resistance and no sharp or rigid edges to the air, but yielding to every breath; the quill-feathers are inelastic, and the outer edge of the first, instead of being plain as in most other birds, is fringed with a finely pectinated or comblike line of short lashes, the terminations of the plumelets which compose the vane; so that,
in winnowing the air, no whistling is produced, as it is by the sharp cutting wing of the pigeon : such is the plumage of the owl. In the various tribes of birds whose home is on the ocean, we see another modification. Here the body is clothed with an inner garment of down wadded close and thick, as well for the sake of warmth as in order to prevent the water from penetrating; over this is the cloak of outer feathers, closely compacted together and varnished with an oily fluid to throw the water off, so that the body is doubly protected: such is the plumage of the eider duck. Many more examples we might bring forward to illustrate this part of our subject, for in fact almost every bird, certainly every genus, has its own peculiar style; we shall, however, content ourselves with the hints already dropped, and proceed to the investigation of the structure and mode of growth of these important appendages.
If we take up a feather and examine it, we observe that it consists of three parts; the quill or barrel, the shaft, and the web or vane. The quill is that hollow portion which constitutes the base of the feather, and forms a sheath to the vascular tissue during the exit of the feather from the skin and its future growth. The shaft consists of a white pithy substance, not unlike cork invested in a horny coat, most thick and glossy on its outer aspect, and continued from the quill. The web or vane arises from each side of the shaft, and consists of tapering flattened strips, termed barbs, approximating like the leaves of a book, and furnished at their edges with a row of minute processes called barbules. The origin of every feather is in a glandular pellicle of the skin, whence proceeds a vascular pulp or tissue, which presently becomes invested with several “ layers of condensed cellular membrane, from which the shaft, the filaments of both lateral webs, the colouring matter, and the horny quill are severally produced.” As the feather expands, escapes the confinement of the investing membrane, and attains its full perfection, the vascular pulp now enclosed, except at its root, by the barrel of the feather, at length dries up, and the blood-vessels become obliterated, and in this state it is the well known pith, which we remove from a