_Migrations of Birds._--In all the temperate parts of the globe there are a considerable number of birds which reside only a part of the year, regularly arriving and leaving at tolerably fixed epochs. In our own country many northern birds visit us in winter, such as the fieldfare, redwing, snow-bunting, turnstone, and numerous ducks and waders; with a few, like the black redstart, and (according to Rev. C. A. Johns) some of the woodcocks from the south. In the summer a host of birds appear--the cuckoo, the swifts and swallows, and numerous warblers, being the most familiar,--which stay to build their nests and rear their young, and then leave us again. These are true migrants; but a number of other birds visit us occasionally, like the waxwing, the oriole, and the beefeater, and can only be classed as stragglers, which, perhaps from too rapid multiplication one year and want of food the next, are driven to extend their ordinary range of migration to an unusual degree. We will now endeavour to sketch the chief phenomena of migration in different countries. _Europe._--It is well ascertained that most of the birds that spend their spring and summer in the temperate parts of Europe pass the winter in North Africa and Western Asia. The winter visitants, on the other hand, pass the summer in the extreme north of Europe and Asia, many of them having been found to breed in Lapland. The arrival of migratory birds from the south is very constant as to date, seldom varying more than a week or two, without any regard to the weather at the time; but the departure is less constant, and more dependent on the weather. Thus the swallow always comes to us about the middle {20}of April, however cold it may be, while its departure may take place from the end of September to late in October, and is said by Forster to occur on the first N. or N.E. wind after the 20th of September. Almost all the migratory birds of Europe go southward to the Mediterranean, move along its coasts east or west, and cross over in three places only; either from the south of Spain, in the neighbourhood of Gibraltar, from Sicily over Malta, or to the east by Greece and Cyprus. They are thus always in sight of land. The passage of most small birds (and many of the larger ones too) takes place at night; and they only cross the Mediterranean when the wind is steady from near the east or west, and when there is moonlight.