probably extinct. The Antilles tell a similar tale. The great auk, once common on the British coasts, those of Denmark, the east coast of North America, then restricted to those of Newfoundland, Greenland and Iceland, has been killed by man, and the same fate has overtaken the Labrador duck, the Phillip Island parrot, Nestor productus, and the large cormorant of Bering Island, Phalacrocorax perspicillatus; and how long will the flightless cormorant, Ph. harrisi of the Galapagos, survive its quite recent discovery?
|Fig. 21.—Pied Duck (Somateria labradora), male and female. (From specimens in the British Museum. Reduced.)|
Authorities.—A. Milne-Edwards, Recherches anatomiques et paléontologiques pour servir à l’histoire des oiseaux fossiles de la France (Paris, 1867-1868); F. P. Moreno and A. Mercerat, Catalogo de los Pajaros fosiles de la Republica Argentina. Anales Mus. La Plata, 1891, 21 pls.; O. C. Marsh, Odontornithes: A monograph of the Extinct Toothed Birds of North America (New Haven, Conn., 1880); R. Lydekker, article “Fossil Birds,” in A. Newton’s Dictionary of Birds (London, 1893); Cat. Foss. Birds, Brit. Museum, 1891; K. v. Zittel, Handbuch der Paläontologie, i. 3 (1887-1890); C. W. Andrews, “On the Extinct Birds of Patagonia,” Tr. Zool. Soc. xv., 1899, pp. 55-86, pls. 14-17.
C. Geographical Distribution
The study of the extinct organisms of any country leads to a proper appreciation of its existing flora and fauna; while, on the other hand, a due consideration of the plants and animals which may predominate within its bounds cannot fail to throw more or less light on the changes it has in the course of ages undergone. That is to say, the distribution of forms in time is a subject so much connected with the distribution of forms in space, that the one can hardly be separated from the other. Granting this is a general truth, it must yet be acknowledged as a special fact, that in fossil birds we have as yet but scanty means of arriving at any precise results which will justify bold generalization in the matter of avine distribution. Remains of extinct birds are, compared with those of other classes of vertebrates, exceedingly scarce, and these have been found in very few, widely separated countries. The great problems involved in the study of geographical distribution must therefore be based mainly upon the other classes, both vertebrate and invertebrate, which, moreover, enjoy less great facilities of locomotion than the birds.
Yet it so happens that the great zoogeographical regions of the world, now more or less generally accepted, have been based upon the distribution of birds. The whole subject was properly introduced by Treviranus, who in his large philosophical work devotes considerable space to the “geographical distribution of animals.” Next we have to mention F. Tiedemann, the Heidelberg anatomist, who has been generally ignored, although he surpassed many a recent zoogeographer by the wide view he took of the problem; in fact he was the first to connect distribution with environmental or bionomic factors; e.g. the remark on p. 481 of his work that “the countries of the East Indian flora have no kinds of birds in common with America which are vegetable feeders.” L. K. Schmarda divided the land into twenty-one realms, characterizing these mainly by their birds. P. L. Sclater was the first to divide the world into a few great “regions,” the Palaearctic, Ethiopian, Indian and Australian forming one group, the “Old World” (Palaeogaea); and the Nearctic and Neotropical forming a second, the New World (Neogaea). Birds being of all animals most particularly adapted for extended and rapid locomotion, it became necessary for him to eliminate from his consideration those groups, be they small or large, which are of more or less universal occurrence, and to ground his results on what was at that time commonly known as the order Insessores or Passeres, comprehending the orders now differentiated as Passeriformes, Coraciiformes and Cuculiformes, in other words the mass of arboreal birds. His six main divisions—practically adopted by A. R. Wallace in his epoch-making work—are excellent, taken separately. They express the main complexes of land with their dependencies in well-chosen terms; for instance the “Neotropical region” stands short for South and Central America with the Antilles.
But these six divisions of Sclater and Wallace are not all equivalent, only some are of primary importance; they require co- and sub-ordination. This most important advance was made by T. H. Huxley. Some of the “regions” have now to be called subregions, e.g. the Nearctic and the Palaearctic. The reduction of the Oriental to a subregion, with consequent “provincial” rank of its main subdivisions, will probably be objected to, but these are matters of taste and prejudice. Above all it should be borne in mind that nearly all the last subdivisions or provinces are of very little real value and most of them are inapplicable to other classes of animals.
Besides some occasional references in the text, only a few more of the general works dealing with the distribution of birds can here be mentioned. Especial attention has to be drawn to the article “Geographical Distribution,” in Newton’s Dictionary of Birds. See also A. Heilprin, The Geographical and Zoological Distribution of Animals (New York, 1887); W. Marshall and A. Reichenow, two maps with much detail, although badly arranged, in Berghaus’ Physikalischer Atlas, pt. vi. (Atlas d. Thierverbreitung), (Gotha, 1887); A. Reichenow, “Die Begrenzung zoogeographischer Regionen vom ornithologischen Standpunkte,” Zoolog. Jahrb. iii., 1888, pp. 671-704, pl. xxvi.; E. L. Trouessart, La Géographie zoologique. (Paris, 1890).
The scheme adopted in the following account stands as follows:—
|(A) Austrogaea or I. Australian Region|| New Zealandsubregion. |
|(B) Neogaea or II. Neotropical Region|| Antillean ”|
|(C) Arctogaea||III. Holarctic Region|| Nearctic”|
|IV Palaeotropical Region|| Ethiopian ”|
In the following account the characterization of the various regions and subregions has to a very great extent been adopted from Newton’s article in his Dictionary of Birds, and from the chapter on distribution in the article on “Birds” in the Encyclopaedia Britannica, 9th edition. This applies especially
- Treviranus, Biologie oder Philosophie der lebenden Natur, vol. ii. cap. 4, § 2 (Göttingen, 1803).
- F. Tiedemann, Anatomie und Naturgeschichte der Vögel, vol. ii §§ 127-255 (Heidelberg, 1814).
- L. K. Schmarda, Die geographische Verbreitung der Thiere (Wien, 1853).
- P. L. Sclater on the general geographical distribution of the members of the class “Aves,” 2. Linn. Soc. ii. pp. 130-145, 1858.
- A. R. Wallace, The Geographical Distribution of Animals, with a study of the Relations of Living and Extinct Faunas as elucidating the Past Changes of the Earth’s Surface, 2 vols. (London, 1876).
- T. H. Huxley, “On the Classification and Distribution of the Alectoromorphae,” P.Z.S., 1868, pp. 313-319.