JANUARY.

But

WINTER SONG BIRDS.-It is a common occurrence, which few can have failed to observe, for caged birds of various species to sing during winter, in consequence of their being supplied with abundance of food, and protected from the inclemencies of the weather; since otherwise, very few of these would sing a note. when thus protected, and well fed, Mr. Sweet has had many of our most delicate migratory birds in full song for the greater part of the winter, particularly the black cap (Sylvia atricapilla), the white throat (S. cinerea), and the nightingale (S. luscinia). There are, however, two of our best known birds, who seem to enjoy the cold of the winter months little less than the sunshine of summer, if we may judge by the merry glee which they then display: we allude to the wren (Anorthura communis, RENNIE), but particularly to the redbreast (Sylvia rubecula). White, in his Natural History of Selborne, states, that the wren sings all winter, except during frost; but we have heard it not only singing during intense frost, but what is still more wonderful-during a fall of snow, and that not in a solitary instance, but frequently. We observed this more than once, during the

most inclement days of the preceding winter, which was

OF AMERICAN

more than usually severe. MIGRATION AND EUROPEAN BIRDS. The numerous interesting facts connected with the migration of birds in the splendid works of Wilson and Audubon, lead us to conclude, that the annual migration is much more general in North America, than in Europe, owing no doubt, to the greater severity of the winters there, which would render it impossible for the soft-billed birds to find food. Even in our own country, some of those, which do not migrate, are, in severe winters, exposed to great privations. At first view, it appears not a little singular, that, among birds differing very little in habit, some should remain with us, and others should migrate; but a slight knowledge of Natural History will lead to a solution of the singularity. Soft-billed birds, like the robin, depend upon caterpillars and worms for their principal food; and, as many species of caterpillars live through the winter, such birds are enabled to procure food. In open weather, also, earthworms occasionally make their appearance, as well as small slugs. The redbreast, accordingly, and more particulary the wren, may be seen prying with a keen eye into the roots of trees and shrubs, for the caterpillars, which lurk there, and hopping over the grass-plots in gardens, to pounce upon an earth-worm, that may have strayed from its hole; while the wag-tail (Motacilla lotor, RENNIE), endeavours to pick up a scanty meal of the small winter gnats which occasionally play about running water in fine weather. The winter supply, however, of live insects, would be far from sufficient for the numerous soft-billed birds, which haunt our woods and hedges in

summer; and therefore, it has been so ordained, that the nightingale, the white-throat, and many others, should migrate during the winter to a warmer climate, where they can be in little danger of perishing by famine. The swallows, fly-catchers, and other birds, which capture insects on the wing, would obviously be starved to death at the very commencement of the cold weather.

UTILITY OF SNOW.-Several of our native plants, such as groundsel (Senecio vulgaris), chickweed (Alsine media), the barren strawberry (Dalibarda fragariodes, MICHELI), the red dead nettle (Lamium purpureum), and furze (Ulex Europaus), put forth blossoms in defiance of the cold; they rarely, if ever, at this season, perfect their seeds. It is highly probable, we think, that these and other flowers which brave severe cold, have the power of generating organic heat; for many of them are so delicate in texture that no plausible supposition could be made respecting the rigidity of their fibres or of their sap vessels. Some plants, indeed. manifest a degree of heat enough to affect the thermometer, and all vegetables are some degrees warmer than the surrounding air; a circumstance which enables them to resist the colds of winter. The same fact holds true of seeds which have been self-sown the preceding summer and autumn, and remain, through the winter, on or near the surface of the ground-retaining their life in defiance of frost-till the reviving warmth of spring excites them to germinate.

The fact appears not a little singular, that alpine plants, such as auriculas, some saxifrages, &c. should be of difficult culture in our climate, and are not unfrequently destroyed by our winters, whilst they flourish in

their native snows; but it should be observed, that, in the Alps, where, growing wild, they are, throughout the winter, covered with a complete coating of snow, which, from not being a rapid conductor of heat, is instrumental in the earth's not parting quickly with its warmth, in the same manner as a woollen garment prevents the escape of heat from the body,this protects them through the cold season; whereas, in our climate, these plants are exposed alternately to the severe influence of frost, unprotected by the snow, and to long continued rains. The frost, injuring the structure of the leaves, they become readily rotted by the wet; and, although the plants are not often entirely killed, they are too much injured to ensure a good show of bloom. It is necessary, for the cultivation of the finer sorts of auriculas, &c. to imitate, as far as possible, their native climate, by protecting them in a frame or shed, both from the severe frosts and wet. It is, however, to be remarked, that our climate opposes another and a serious objection to the easy cultivation of this class of plants, arising from the great variation of temperature. Even during the winter months the plants frequently commence growing before the spring arrives, and thus are rendered more obnoxious to the succeeding frosts; and in addition, the strength of the plants (which should be reserved for the great effort to be made in the spring) is exhausted before its due season whilst in the

sun, at once,

Alps they lie entirely dormant, until the melts the snow, and calls them into life and blossom. To prevent the plant growing out of its season, it is found best to place the pots in a part of the garden exposed to a northern or western aspect.

There is a remarkable fact mentioned by M. de la Roque, with respect to the cedars of Lebanon, which on their native mountains, as soon as the winter snows begin to fall, change their irregular diffusion of branches into a regular uniform pyramidal cone; but as the snows melt with the return of spring, they again spread out their boughs. We know not whether the cedars in this country have similar habits.

The check given to the flow of sap and increase of growth in trees by the winter's cold, is the cause of those circles which appear on cutting a tree across, and by which its age may be counted. That cold is the chief cause of this, appears from the circles being more broad and distinct on the northern side of the tree.

SEA-SWELLS.-If a rope of several fathoms be suspended at some height, and not drawn very tight, and one end bent by the hand into the form of an, and suddenly let go-a waving motion will be communicated through the whole extent of the rope of a similar form, though not quite so distinct. After arriving at the opposite end of the rope, the same waving motion will travel back again, diminishing in intensity as it proceeds, precisely in the same way as the pendulum of a clock will do when suspended from a nail. Those who can understand this will find no difficulty in comprehending the swell produced in the sea for some time after it has been blowing hard. The weight of the water, or the force with which it tends towards the centre of the earth, is to it what the stretching is to the cord, and it is the wind acting on the surface, which raises the water and throws it into the form of an n, as in the former instance. Now we have seen that the