Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/782

Rh BIRDS [MIGRATION. both of Malacca and of Borneo, but it seems to have much less peculiarity than the latter s. We then have Java, the best-explored, the most thickly- peopled, and, proportionately to its fauna, the most pecu liar, perhaps, of the Indo-Malay Islands. Here we find about 270 species of Land-birds, of which about 45 are peculiar most of them being from the mountains in the western part of the island. The reappearance in Java of several Burmese species, as Crypsirhina varians, Picits analis, Pavo muticus, and others, which do not occur in the Malay Peninsula south of Penang, is very remark able. Of Bali, so interesting as the southern outpost of the Region, we only know from Mr Wallace that he saw there several Birds highly characteristic of Javan ornithology, and whether the island has any peculiar species nowhere appears. We are then brought to the brink of that re markable strait through which runs &quot; Wallace s Line,&quot; and crossing it find ourselves at once in the Australian Region, with which we began this protracted dissertation. rmity It is, of course, much to be regretted that at present our oni- information does not allow of our treating all the Six Zoo- !gj]j le ing equally with their several component portions. That this will be possible in a few years, as materials are accu mulated, none can doubt ; but as yet we are far from the attainment of so desirable an end, and must be content to make the most of what we have. Want of space, also, has hindered the proper consideration here of many points that fully deserve notice, and especially the negative character istics of the different Regions often quite as important as those which are positive. Of the imperfections of the preceding sketch no one can be more painfully aware than its author, but its very imperfections may serve a useful purpose in drawing attention to the districts about which least is known. Yet it would be affectation for him not to believe that it has some actual merit, but that merit is greatly if not chiefly due to the kindness of Mr Wallace, who, in the manner already stated, has allowed his forth coming work to be laid under contribution, though in several respects its conclusions are not here adopted. That work, when published, will unquestionably form a foundation on which a noble superstructure will ultimately be erected, but it were vain to anticipate the ends which such a build ing will one day serve, and it would be beyond our scope to enter into any theoretical disquisition on the deductions which follow from the facts here advanced. MIGRATION. Most strangely and unaccountably confounded by many writers with the subject of Distribution is that of Migra tion. True it is that owing to the vast powers of loco motion possessed by nearly all Birds, we have individuals aliens belonging in the main to certain groups, but by no means rently always confined to them, straying from their proper quar- )rm to land of their birth, but from the country whither they are ordinarily bound in their journeys, to reach which is the object wherefore such journeys are undertaken. It may be that in some measure this erraticism is governed by fixed laws, and indeed indication is not wanting that such laws exist, though as yet we know much too little to lay them down with any approach to confidence. But it is obvious on reflection that granting the existence of most rigorous laws of this kind determining the flight of every winged vagabond they must be very different from those which are obeyed by Birds commonly called &quot; Migratory,&quot; and migrating year after year according to a more or less fixed rule from one locality to another with the seasons cs they roll. The former laws would seem to be created or controlled by purely external circumstances, which if they possess any periodicity at all possess a periodicity of cycles, and are most likely dependent in the main on cycles of the weather, but on this point observation has not yet supplied us with the means of avoiding speculation. We may indeed say almost without much risk of error that so many individuals of a foreign species whether North- American or Asiatic will occur in Great Britain so many times in the course of a term of years ; but, though we may safely predict that if they appear at all they will do so at a certain season, it is impossible to make a forecast as to the year in which an example will turn up, or whether in one year some half-dozen may or may not occur. The matter thus becomes a matter of averages, and like all such is open to the influence of many perturbants, not that such may not well be subject to some law of which we are ignorant. Besides this, the average is hard to strike, de pending as it must on the existence of favourably-placed and watchful observers. Moreover if we consider that the number of competent observers, though possibly greater in England than anywhere else in the world, has been at all times small, it is not surprising that little has been effected towards the compassing of any definite notion on this head. At present we can but attribute the appearance of foreign stragglers on our shores, and no doubt the same may be said of other countries, to the influence of storms which have driven the wanderers from their course, and though other more remote causes may possibly be assigned, there seems to be none but this on which we can safely rely. Consequently until the periodicity of storms is brought within our knowledge we must be content to abide in our ignorance of the laws which govern the appearance of the strangers. Still confining our remarks to the British Islands, the effect of these laws is in some degree constant. Singular as it may appear, the greatest number of North- American Birds and especially of the Limicolcc. or Shore- birds, which are recorded as having occurred in this country have been met with in the eastern part of England or Scotland. There are two ways of accounting for this fact, the first of which is the unfortunate scarcity of observing naturalists in Ireland and on its western coast especially, and this is by no means to be overlooked ; but it may be remarked that in no part of the United Kingdom is the profession of the gunner more enthusiastically followed than in the sister island, and the men who pursue that vocation are all alive to the mercantile value of any strange bird which may fall in their way. Of course they have no means of knowing what it is, yet as their spoils are sent for sale to the nearest market, it cannot but happen that if many examples of North-American species were procured by them, some proportion of these would find their way to the notice of the amateur naturalist and by him be re corded in the public prints. 1 Now, as compared with Great Britain, this so rarely occurs in Ireland that it is by no means unfair to draw the inference that Transatlantic Birds are there far less frequently met with. The second mode of accounting for the fact above stated is that the majority of North-American Birds which occasionally visit Europe are of species which breed in somewhat high northern latitudes. On their way thence to their winter- quarters, some are driven out to sea by violent westerly gales the strongest winds, be it remembered, that prevail 1 It seems also not unlikely that the very scarcity of rare birds in Ireland is one reason why there are so few ornithologists in that country, for here it is not uncommon for a man to have his attention first called to zoology by meeting with some strange animal be it beast, bird, beetle, or butterfly, and for such a man afterwards to become no mean field-naturalist. Appear ance ot Britain
 * logical Regions of the globe on a uniform plan, or of deal-
 * ters and occurring in places far removed, not only from the