PDF - Wallace Online

in ANIMAL LIFE IN THE TROPICAL FORESTS 295These are such common birds in all temperate countriesthat itmay surprise many .readers to learn that they arenevertheless a characteristic tropical group. That such is thecase, however, will be evident from the fact that only sixteenspecies are known from the whole of the temperate parts ofEurope, Asia, and North America, while about 330 speciesinhabit the tropics. Again, the great majority of the speciesare found congregated in the equatorial zone, whence theydiminish gradually toward the limits of the tropics, and thensuddenly fall off in the temperate zones. Yet although theyare pre-eminently tropical or even equatorial as a group, theyare not, from our present point of view, of much importance,because they are so shy and so generally inconspicuous thatin most parts of the tropics an ordinary observer might hardlybe aware of their existence. The remark applies especially toAmerica and Africa, where they are neither very abundantnor peculiar ;but in the Eastern hemisphere, and especiallyin the Malay Archipelago and Pacific islands, they occur insuch profusion and present such singular forms and brilliantcolours, that they are sure to attract attention. Here wefind the extensive group of fruit -pigeons, which, in theirgeneral green colours adorned with patches and bands ofpurple, white, blue, or orange, almost rival the parrot tribe ;while the golden -green Nicobar pigeon, the great crownedpigeons of New Guinea as large as turkeys, and the goldenyellowfruit-dove of the Fijis, can hardly be surpassed for beauty.Pigeons are especially abundant and varied in tropicalarchipelagoes, so that if we take the Malay and Pacific islands,the Madagascar group, and the Antilles or West Indianislands, we find that they possess between them more differentkinds of pigeons than all the continental tropics combined.Yet further, that portion of the Malay Archipelago east ofBorneo, together with the Pacific islands, is exceptionallyrich in pigeons ;and the reason seems to be that monkeysand all other arboreal mammals that devour eggs and youngbirds are entirely absent from this region. Even in SouthAmerica pigeons are scarce where monkeys are abundant, andvice versd, so that here we seem to get a glimpse of one of the