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THE STORY OF THE ISLES OF THE SEA. 337 THE STORY OF THE ISLES OF THE SEA, TOLD BY THE FOWLS OF THE AIR. By H. B. TRISTRAM, LL.D., F.R.S., CANON OF DURHAM. IV.-THE PACIFIC OCEAN. HE story of the Isles of thePacific receives and the Ladrones in the Australian area, T not less illustration from the examination leaving Japan in the old world, or Pala!arctic of their birds than does that of the Isles of region; and of course embracing the Sand wich the Indian Ocean. Vast as is the area of the Islands in the Pacific area, which (speaking Pacific, there is, with one exception, that of as a naturalist) does not comprise the Loo­ the Galapagos, a homogeneity in the general choo Islands nor the Aleutian. South-west­ character of its bird-life, and a distinctness ward from Bali the line runs down beyond withal in the different groups, which separate the west of Australia, where there are no them clearly from each other, and still more islands till we reach the Mascarenes, and widely from the islands of the Indian Ocean. then, sweeping southward, it includes New Nor, although this line of demarcation be­ Zealand, the Chatham Islands, and all the tween the two oceans be apparently arbi­ Oceanic groups in the South Pacific, except­ trary, yet, so far as regards the forms of ing the Galapagos, which are American in insular life, is it other than exact, accurate, their affinities. and sharply defined. If we glance at a map But what are the features which determine of the vast insular region to the south-east "Wallace's line"? To speak of the great of Asia, there is nowhere any visible geo­ families of birds only, on the one side, the graphical break from Malacca to Tasmania. Indian, are the vultures, the pheasants, the One close chain of islands links Australia barbets, the bulbuls, and the true finches, to Asia. with all their innumerable species. In fact, But let us examine the teeming bird-life of of the pheasant, barbets, and bulbuls, the that exuberant region, and ornithology sup­ Indian region may be said to be the home. plies us with a dividing line, which seems to Not one of them is found on the other side indicate a geologic separation of infinite anti­ of the line. Then the thrushes and the quity. A string of islands runs east of Java warblers (sylviadae), so endless in variety, and to New Guinea, never more than a few miles so numerous in individuals in the old world apart, apparently all of a similar character. of these but a few straggling species cross the There is no special feature to distinguish one line. Most striking of all, the woodpeckers, channel from another. Yet between two of of which there are over three hundred these islands, the observant eye of Mr. A. R. species, are absolutely unknown in the Wallace, who stands at the head of all natu­ Australian region, excepting that some four ralists in scientific exploration, has detected or five species just cross the boundary, and the line which separates India and Australia. are found here and there in Lombok, Celebes, The channel between the small islands of and Moluccas, but not one in Australia or Bali and Lombok is not more than fifteen the Pacific. So much for the great bird­ miles wide, but west of it all life is, speaking families conspicuous for their absence. generally, Indian in its character; east of it, Still more remarkable are the new and un­ all is Australian. From the Himalayas to wonted forms to which we are introduced across Bali, there is no break, only a gradual local the line. They differ infinitely more from the variation in the animals, birds, reptiles, in­ feathered inhabitants of any other part of the sects, and molluscs. In Lombok the world, than the birds of the rest of the world naturalist finds himself in a new world. do among themselves. The honeysuckers, a This line of demarcation, now familiar to all family of birds remarkable for its structural students of the subject as" Wallace's line," can peculiarities, having a brush at the end of be traced with more or less precision separating its tongue, with which it sweeps up the two entirely distinct portions of the earth's nectar of flowers, and abounding in genera surface. From Bali it runs northwards and species (no less than one hundred and through the straits of Macassar, dividing thirty species are already known), is never Borneo from Celebes, then trending eastward, found out of this Pacific area (if we except it passes between the Philippine Islands on one species which does cross from Lombok the north, and Sanguir to the south, and to Bali), but is represented by numerous further onward embraces the Pelew Islands varieties in every, even the remotest, corner XVIII-24 GOOD WORDS. of that vast space. Other great families are distinct areas of insular bird-life, varying from only feebly developed outside the Austra­ the oldest to the most recent, structurally lian region, but are most characteristic in considered, of the island bird faunas. Standing it. Such are the moreporks (Podargus), out distinctly from all others, the most pecu­ the flower-peckers (Dicaeum), the caterpil­ liar and the oldest in the world, is the most lar eaters (Campephaga), the swallow fly­ recent of England's great colonies, New Zea­ catchers (Artamus), and especially the land, with the Chatham and Auckland Isles, thick-headed shrikes (Pachycephala). Of Lord Howe's, Norfolk, and Philip Islands. birds of universal distribution, the king­ Second, but zoologically far more modern, fishers and the pigeons are here found in a is Australia, with its satellite, Tasmania. variety of species and a gorgeousness of Third in antiquity we may place the Papuan plumage elsewhere unrivalled. But none of region, New Guinea, with Timor, Celebes, these are so strangely diverse from all others Moluccas, and their numerous dependant as are the ostrich-like emeus of Australia, islands. Fourth appear to rank the Sandwich the wingless rails, the resplendent rifle- birds, Islands. Fifth, by far the widest in area, the the gorgeous birds of paradise of Papua, Polynesian Archipelago, with countless islets, bower-birds, lyre-birds, and most of all, the scattered over ninety degrees of longitude weird-like kiwi or Apteryx and the recently and forty of latitude, from the Pelew Islands exterminated colossal moas (Dinornis) of to Easter Island. Lastly we have the most New Zealand. modern of all, the Galapagos, which might, What is the story of the isles which perhaps, be more justly treated as an outlier all this tells? Why, without any sudden of South America, but the exceptional natural change of climate, with no perceptible differ­ history of which casts much light on the ence in geologic character, should that line variation and specialisation of species. of Wallace prove a great barrier, which these The Galapagos Islands, lying just under birds pass neither one way nor the other? It the equator, six hundred miles westward of cannot be want of power of flight, for all, South America, are a striking contrast in excepting the brevi pennant or wingless their general character and appearance to species, cross infinitely wider expanses of other tropical islands. Spread over a space water elsewhere. It tells us, surely, that the of two hundred miles from north to south, Australian region is no mere prolongation of and one hundred and eighty from east to Eastern Asia, but that, while there has been, west, they are wholly volcanic. On many whatever may have been from time to time of them the volcanoes are still active, and the oscillations, upheavals, or depressions of one crater attains a height of four thousand the earth's surface, more or less communi­ seven hundred feet. The streams of lava cation between the whole Indian region as have sometimes so heated the water as to far as Bali, from a period infinitely more compel ships to run from their anchorage, remote, the sea has ever flowed between that where they found a sea temperature of 150° and island and Lombok, and no upheaval has the atmosphere 147°. Notwithstanding these ever united them; that the fissure between occasional irregularities, the temperature is them is one that has probably existed ever usually moderate for an equatorial region, since the crust of the earth first solidified. If, for the Galapagos are struck by the polar cur- as in the course of these papers we shall rent from the south. From the same cause, endeavour to show, the bird-life of these probably, there is a total absence of the islands is really the most antique on the face coralline insects, so universal elsewhere of the earth, it seems difficult indeed to round the Pacific Islands. avoid this conclusion, or not to admit that But even this is scarcely enough to ac­ here ornithology actually demonstrates a count for the strange barrenness, the mea­ great geological fact, which neither the com­ greness of vegetation, its stunted growth, for position of the rocks nor any palreontological the most part wretched little weeds, more traces could have suggested. becoming an arctic than an equatorial When we proceed to classify and group the flora, and for the abnormal absence of birds of these islands, scattered over one­ brilliant colours, both in animal and vege­ third of the earth's surface, we find differ­ table life. The largest island of the group, ences so great and so marked that we are Albemarle, eighty miles in length and in one led to suggest that the Pacific region is but part fifty miles wide, is, excepting on its a comprehensive term for various areas not southern side, miserably barren, covered less distinct than the other natural regions of with immense streams of black naked lava, the globe.

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