HYDERNATING ANIMALS WHICH MIGRATE.
THIS subject has long occupied the attention of naThis subject has long occupied the attention of na- turalists ; and several important observations have been published by different authors. It is chiefly, however, as it regards birds, that the subject is deserving of particular - consideration. We are acquainted with but few circum stances connected with the migration of quadrupeds. Limited in their powers of locomotion, their range of tra velling is confined, so that other means are provided for their safety and sustenance during winter. The chcirop tera are well fitted for migrating ; and accordingly we find that some species are known to do so. In Italy, the com mon hat (Yespertilio murinus) abounds ; but it migrates southwards at the approach of winter, and is not found in any of the caves in a torpid state. The V. noctula, how ever, arrives annually to winter, although it retires to spend the summer in more northern regions. Dr Barton in forms us, that some species of dipus migrate from the northern to the southern parts of America during winter. Alany of the ruminating animals shift their habitations ac.
cording to the changes of the year. Thus, the stag and the roebuck leave the alpine regions at the approach of winter, and seek protection in the more sheltered plains. More extensive migrations are performed by the palmated quadrupeds, particularly the seals. These shift their sta tions to reach safe breeding places, in whatever country they live in. But the common seal (Phoca vitulina) often performs regular migrations in quest of food. In the Statistical Account of the parish of North Knapdale, we ate told that the lake called Lochow, about twenty miles in length, and three miles in breadth, " abounds with plenty of the finest salmon ; and, what is ,uncommon, the seal a comes up from the ocean, through very rapid river, in quest of this fish, and retires to the sea at the approach of winter." Another species, the P. Groenlandica, seems to seek more temperate regions during the winter. Seals of this kind, says Ilorrebow in his History of Iceland, " ar rive annually in the month of December, especially about the northern parts of the country, and generally stay till May, at which time those that escape the Icelanders de part." A few curious facts regarding the migrations of
the Cetacea may be found under the article GREENLAND. Several kinds of small whales visit the coasts of Scotland, chiefly during the autumnal months ; but we are ignorant of the places from whence they come, and unacfluainted with the laws of their migration.
Migration of Birds.
The migrations of the feathered race, as connected with their hybernation, have been the subject of popular ob servation since the days of the prophet Jeremiah. " Yea, the stork in the heaven knoweth her appointed times ; and the turtle, and the crane, and the swallow, observe the time of their coming," (ch. viii. v. 7.) Many important facts have been ascertained, and a few general conclusions have been established. But the subject is still far from being exhausted ; nay, without fear of contradiction, we may venture to assert, that it is but very imperfectly under stood by naturalists in general. Popular errors have gained admittance as scientific documents, and the well authenticated facts have been suffered to remain in their original detached form, destitute of connection and arrange ment.
It is not our intention to enter into any minuteness of detail regarding the migrations of the different species of birds. This has already been done under the article BIRDS, where the reader will find a statement of several facts con nected with the migration of our native species. And he may also consult at his leisure, the ornithological produc tions of Pennant, White, and Montagu. Our observations in this place will be of a general nature, and will have for their object to ascertain the laws of migration, and the cir cumstances under which it takes place.
Migrating birds may be divided into two classes, front the different seasons of the year in which they arrive or depart. To the first class will belong those birds which arrive in this country in the spring, and depart in autumn, and are termed Summer Birds of Passage. The second will include those which arrive in autumn, and depart in spring, and are called Winter Birds of Passage.