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change, it is only from motives of famine or of fear. There are some sorts, however, called birds of passage, which remove to warmer or colder climates, as the air or their peculiar nourishment invites them. Thus the starling in Sweden, at the approach of winter, finding subsistence no longer in that kingdom, descends every year into Germany; and the hen chaffinches of the same country are seen every year to fly through Holland, in large flocks, to pass their winter in a milder climate. Others, with a more daring flight, traverse the ocean, and undertake voyages that might intimidate even human perseverance. Thus quails in the spring leave the burning heat of Africa for the milder sun of Europe, and when they have passed the summer with us, steer their flight back, to enjoy in Egypt the temperate air which they can no longer find with us. They often fly in such numbers, that to mariners at sea they appear to cover the skies like a cloud, and sometimes, wearied by the length of their flight, drop down upon deck, an easy prey to the spectators.

From some accounts published in the Philosophical Transactions, it would seem that swallows do not migrate in the same manner, but continue torpid all the winter; but I think the testimonies in favour of their migration are more cogent than those against it. All those who have sailed to the tropical climates, are convinced, by every day's experience, that they are seen flying in large flocks, in order to enjoy near the equator a warmer air. But not to enter into a discussion of little importance, wild ducks and cranes, at the approach of winter, generally go in search of milder climates, and assemble together for that purpose at a certain time of the year. Nor does this seem to be the deliberation of a day; they sometimes assemble and part different ways, in order to meet a second time; however, at length, as if the migration were unanimously resolved upon, they rise all at once and decamp in a body. It is not unpleasing to

observe the order of their flight. They generally range themselves into one large column, or sometimes forming two columns, joining in an angle like the letter V, while the fowl which makes the point seems to cleave the air to facilitate the passage of those which are to follow. But it continues this laborious employment only for a certain time; after which, falling back into the rear, another takes the place. The prodigious length of their passage is surprising, and how they support themselves in the flight; but the regularity of their motions is not less admirable, and that spirit of society with which they seem obedient to laws for the general welfare. Both young and old are always found at the place of general rendezvous, nor are they ever at a loss to take the direct road to their destined stations.

Thus there are some birds which may properly be called the inhabitants of every part of the earth; but in general every climate has birds peculiar to itself alone. The feathered inhabitants of the temperate zone chiefly excel in the music of their notes; those of the torrid zone in the bright and vivid colours of their plumage; the frigid zone, on the other hand, where the seas abound with fish, are stocked with fowls of the aquatic kind, in much greater variety than are to be found in our parts of Europe.

In general, every bird resorts to those climates where its food is found in plenty, and always takes care to hatch its young at those places, and in those seasons, where provisions are in the greatest abundance. The large birds, and those of the aquatic kind, choose places as remote as possible from man, as their food is different from that which is cultivated by human industry; some birds, which have only the serpent to fear, build their nests in such a manner as to have them depending at the end of a small bough, and the entrance from below; but the little birds, which live upon fruits and corn, are found in the greatest plenty in the most

populous countries, and are too often unwelcome intruders upon the fruits of human labours. In making their nests, therefore, the little birds use every art to conceal them from man, while the great birds use every precaution to render their's inacessible to wild beasts, or vermin. The unerring instinct which guides every species in contriving the most proper habitation for hatching their young, demands our observation. In hot tropical climates nests of the same kind are made with less art, and of less warm materials, than in the temperate zone, for the sun in some measure assists the business of incubation. In general, however, they build them with great art, and line them with such substances as keep or communicate warmth to their eggs. Nothing can exceed their patience while hatching; neither the calls of hunger, nor the near approach of danger could drive them from the nest; and though they have been found fat upon beginning to sit, yet before the incubation is over the female is usually wasted to a skeleton. The male ravens and crows, while the hens are sitting, take care to provide them with food; while other birds, such as pigeons and sparrows, take their turns, the male relieving the female at proper intervals. Sometimes, however, the eggs acquire a degree of heat too great for the purposes of hatching; in such cases, the hen leaves them to cool a little, and then returns with her usual perseverance and pleasure. When the young brood comes forth, nothing can exceed the industry and the seeming pride of the parents; the most timid becomes courageous in their defence; and 'provides them with food proper for their age or kind. Birds of the rapacious kind become at this season more than ordinarily ravenous, and those of the granivorous sorts discontinue their singing, entirely taken up in procuring subsistence for their young.

Of all birds the ostrich is the greatest, and the American humming bird the least. In these the gradations of nature

are strongly marked, for the ostrich in some respects approaches the nature of that class of animals immediately placed above him, namely quadrupeds, being covered with hair, and incapable of flying; while the humming bird, on the other hand, approaches that of insects. These extremities of the species, however, are rather objects of human curiosity than use; it is the middle orders of birds, which man has taken care to propagate and maintain; these largely administer to his necessities and pleasure, and some birds. are even capable of attachment to the person that feeds them. How far they may be instructed by long assiduity, is obvious from a late instance of a canary bird, which was shewn in London, and which had been taught to pick up the letters of the alphabet at the word of command. Upon the whole, however, they are inferior to quadrupeds in their sagacity; they are possessed of fewer of those powers which look like reason, and seem, in all their actions, rather impelled by instinct than guided by choice. (1)

(1) [“ Having_thus given a short history of Birds, I own I cannot take leave of this most beautiful part of the creation without reluctance. These splendid inhabitants of air possess all those qualities that can sooth the heart and cheer the fancy. The brightest colours, the roundest forms, the most active manners, and the sweetest music. In sending the imagination in pursuit of these, in following them to the chirruping grove, the screaming precipice, or the glassy deep, the mind naturally lost the sense of its own situation, and, attentive to their little sports, almost forgot the task of describing them. Innocently to amuse the imagination in pursuit of these is wisdom; and nothing is useless that, by furnishing mental employment, keeps us for a while in oblivion of those stronger appetites that lead to evil. But every rank or state of mankind may find something to imitate in those delightful songsters, and we may not only employ the time, but mend our lives by the contemplation. From their courage in defence of their young, and their assiduty in incubation, the coward may learn to be brave, and the rash to be patient. The inviolable attachment of some to their companions may give lessons of fidelity; and the connubial tenderness of others be a monitor to the incontinent. Even those that are tyrants by nature never spread capricious destruction; and, unlike man, never inflict a pain but when urged by necessity."-Animated Nature, vol. vi. p. 148.]

PART III-OF FISHES.

THE productions of nature, as they become less perfect, grow more numerous. When we consider what numberless sorts have hitherto escaped human curiosity, what a variety of Fishes are already known, and the amazing fecundity of which they are possessed, we are almost induced to wonder how the ocean finds room for its inhabitants. A single fish is capable of producing eight or ten millions of its kind in a season; but nature has happily obviated this hurtful increase, by making the subsistence of one species depend on the destruction of another. The same enmities that subsist among land animals prevail with equal fury in the waters, and with this aggravation, that by land the rapacious kinds seldom devour each other, but in the ocean it seems an universal warfare of each against each. The large devour the small even of their own species, and these, in their turn, become the tyrants of such as they are able to destroy.

Fishes in general may be divided into those that breathe through lungs, and have red blood circulating through their veins; and those that respire through the gills, and whose circulating juices are limpid and colourless. The first sort, which comprehends all of the cetaceous or whale kind, are possessed of a greater degree of heat than the element they inhabit, are frequently obliged to come to the surface of the water to respire fresh air, and, though they are properly inhabitants of the ocean yet are capable of being suffocated in it. They use coition, bring forth their young alive, nourish them with their milk, and resemble quadrupeds as to their internal conformation. The latter sort, on the contrary, are as cold as the element in which

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