A spirit of change and a restlessness seemed to pervade the very inhabitants of the forest. A countless multitude of squirrels, obeying some great and universal impulse, which none can know but the Spirit that gave them being, left their reckless and gambolling life, and their ancient places of retreat in the north, and were seen pressing forward by tens of thousands in a deep and sober phalanx to the South. No obstacles seemed to check this extraordinary and concerted movement: the word had been given them to go forth, and they obeyed it, though multitudes perished in the broad Ohio, which lay in their path.

This species of squirrel has occasionally excited the wonder of the populace by its wandering habits and its singular and long migrations. Like the lemming (Lemmus Norvegicus) of the Eastern continent, it is stimulated either by scarcity of food, or by some other inexplicable instinct, to leave its native haunts, and seek for adventures or for food in some (to it) unexplored portion of our land.

The newspapers from the West contain many interesting details of these migrations; they appear to have been more frequent in former years than the present time. The farmers in the Western wilds regard them with sensations which may be compared to the anxious apprehensions of the Eastern nations at the flight of the devouring locust. At such periods, which usually occur in autumn, the squirrels congregate in different districts of the far North-west; and in irregular troops bend their way instinctively in an eastern direction. Mountains, cleared fields, the narrow bays of some of our lakes, or our broad rivers, present no unconquerable impediments. Onward they come, devouring on their way every thing that is suited to their taste, laying waste the corn and wheat-fields of the farmer; and as their numbers are thinned by the gun, the dog, and the club, others fall in and fill up the ranks, until they occasion infinite mischief, and call forth more than empty threats of vengeance. It is often inquired, how these little creatures, that on common occasions have such an instinctive dread of water, are enabled to cross broad and rapid rivers, like the Ohio and Hudson for instance. It has been asserted by authors, and is believed by many, that they carry to the shore a suitable piece of bark, and seizing the opportunity of a favourable breeze, seat themselves on this substitute for a boat, hoist their broad tails as a sail, and float safely to the opposite shore. This together with many other traits of intelligence ascribed to this species, we suspect to be apocryphal. That they do migrate at irregular, and occasionally at distant periods, is a fact sufficiently established; but in the only two instances in which we had opportunities of witnessing the migrations of these squirrels, it appeared to us, that these were not only unskilful sailors but clumsy swimmers. One of these occasions, (as far as our recollection serves us), was in the autumn of 1808 or 1809; troops of squirrels suddenly and unexpectedly made their appearance in the neighbourhood; among them were varieties not previously seen in those parts; some were broadly striped with yellow on the sides, and a few had a black stripe on each side, bordered with yellow or brown, resembling the stripes on the sides of the Hudson's Bay Squirrel (S. Hudsonius.) They swam the Hudson in various places between Waterford and Saratoga; those which we observed crossing the river were swimming deep and awkwardly, their bodies and tails wholly submerged; several that had been drowned were carried downwards by the stream; and those which were so fortunate as to reach the opposite bank were so wet and fatigued, that the boys stationed there with clubs found no difficulty in securing them alive or in killing them. Their migrations on that occasion did not, so far as we could learn, extend farther eastward than the mountains of Vermont; many remained in the county of Rensselaer, and it was remarked that for several years afterwards squirrels were far more numerous there than before. It is doubtful whether any ever return to the West, as, finding forests and food suited to their taste and habits, they take up their permanent residence in their newly explored country, where they remain and propagate their species, until they are gradually thinned off by the increase of inhabitants, new clearings, and the dexterity of the sportsmen around them. The other instance occurred in 1819, when we were descending the Ohio river in a flat-boat, or ark, chiefly with the intention of seeking for birds then unknown to us. About one hundred miles below Cincinnati, as we were floating down the stream, we observed large number of squirrels swimming across the river, and we continued to see them at various places, until we had nearly reached Smithland, a town not more than about one hundred miles above the mouth of the Ohio.

At times they were strewed, as it were, over the surface of the water, and some of them being fatigued, sought a few moments' rest on our long "steering oar," which hung into the water in a slanting direction over the stern of our boat. The boys, along the shores and in boats, were killing the squirrels with clubs in great numbers, although most of them got safe across. After they had reached the shore we saw some of them trimming their fur on the fences or on logs of drift-wood.

The most interesting feature in the habits of this animal is the remarkable migration performed at times by large bodies of them. ... Immense numbers congregate in autumn, and move off together, continuing their progress in the same general direction, whatever it may be, not even turning aside for large streams. Ordinarily averse to entering the water, they now take to it boldly, and, though swimming with difficulty, manage to cross broad rivers, like the Niagara and the Ohio, though many are drowned in the attempt. The vulgar notion that squirrels, in crossing water, "are ferried over on bits of wood and bark, using their tails for sails," is, it is perhaps needless to say, entirely fabulous. Sometimes, when on these migrations, especially after crossing rivers, the squirrels become so fatigued as to be easily captured, and thousands are then killed by boys armed merely with sticks and stones. I learn from Dr. John A. Kennicott that, during one of these migrations, innumerable squirrels swam across the river Niagara, and landed near Buffalo, New York, in such a state of exhaustion that the boys caught them in their hands, or knocked them from the fences and bushes with poles. It must not be supposed, however, that the squirrels, in these migrations, rush ahead without stopping, or turning to the right or left for food. Better would it be for some unhappy farmers if such were the case, for ill fare the corn-fields which they visit. Generally, they are observed to make their appearance in unusual abundance, running along the fences, and up every tree; and, though they may often go out of their way to follow a fence, or to enter the woods, in preference to crossing open ground, or even to stay some time in one locality, they are always tending forward more or less rapidly in one direction.

The reason for these migrations is not satisfactorily explained. That they are caused by want of food is hardly probable, as the squirrels are found to be fat at the time, and as often leave localities abounding with food as otherwise. After one of these grand migrations, very few of the species are found in the localities from which they have moved, and these, as if alarmed at the unusual solitude, are silent and shy. They rapidly increase in numbers, however, and, in a few years, are as abundant as before. I am not aware that they ever migrate except when exceedingly abundant. Of these immense hordes, but few probably survive. No sudden increase in their numbers was heard of in Southern Wisconsin after the several migrations from Northern Illinois. Many are drowned in attempting to cross streams as has been stated; not a few are destroyed by man; some die from utter exhaustion; and, when forced to travel, in an unnatural manner, upon the ground, they fall an easy prey to rapacious birds and mammals, all of which feast when the squirrels migrate. I learn from Dr. Hoy, that one of these migrations is said to have taken place in Southern Wisconsin in 1842; he witnessed another in 1847, and a third in 1852. From these facts, and from observations made in Ohio and elsewhere, he is of the opinion that the migrations, in most cases, at least, occur at intervals of five years; and, if he be right, the squirrels, which are now exceedingly abundant again in Southern Wisconsin, may be expected to migrate in the autumn of 1857. He further says, that the migrations observed by him, in Southern Wisconsin, occurred when the mast was exceedingly abundant and the squirrels in excellent condition. Near Racine, they were observed passing southward in very large numbers for about two weeks, at the end of September and the beginning of October; and it was a month before all had passed. They moved along rather leisurely, stopping to feed in the fields, and upon the abundant nuts and acorns of the forests. So far had they departed from their accustomed habits that they were seen on the prairie, four or five miles from any timber; but even there, as usual, they disliked to travel on the ground, and ran along the fences wherever it was possible.