features of the whole region are here well represented, e.g. Rhea, Tinami, Chauna, Dicholophus, Attagis, Pteroptochidae, and indeed therein we find some of the best evidence of the antiquity of its population, both recent and extinct (cf. the numerous fossils of the Santa Cruz formation), and also the nearest resemblance to the fauna of Austrogaea.
(C) Arctogaea is Huxley’s well-chosen term for all the rest of the world (including the Nearctic, Palaearctic, Indian and Ethiopian regions of P. L. Sclater) in opposition to Notogaea. Faunistically, although not geographically, the Nearctic and Palaearctic areas must form the two subdivisions of one great unit, for which the “Holarctic region” is now the generally accepted term.
The Holarctic Region, comprising North America and the extratropical mass of land of the Old World, may from an ornithological point of view be characterized by the Colymbi, Alcidae, Gallidae or Alectoropodous Galli, and the Oscines, which have here reached their highest development; while Ratitae, Tinami, Psittaci, and non-Oscine Passeres (with the exception of Tyrannidae extending into North America and Conurus carolinensis) are absent.
Nearctic Subregion.—The close affinity of North America with the Palaearctic avifauna becomes at once apparent if we exclude those groups of birds which we have good reason to believe have their original home in the Neotropical region, notably numerous Tyrannidae, humming-birds and the turkey-buzzards.
The following groups may be mentioned as characteristic and typically American, and, since we consider them as comparatively recent immigrants into the Neotropical region, as originally peculiar to the Nearctic area: Mniotiltidae, Vireonidae, Icteridae, Meleagris and various Tetraoninae. Restricted to and peculiar to the sub-region is only the little Oscine family of Chamaeidae, restricted to the coast district of California. “More than one-third of the genera of Nearctic birds are common also to the Palaearctic subregion. If we take the number of Nearctic species at 700, which is perhaps an exaggeration, and that of the Palaearctic at 850, we find that, exclusive stragglers, there are about 120 common to the two areas. Nearly 20 more are properly Palaearctic, but occasionally occur in America, and about 50 are Nearctic, which from time to time stray to Europe or Asia. This, however, is by no means the only point of resemblance. Of many genera, the so-called species found in the New World are represented in the Old by forms so like them that often none but an expert can distinguish them, and of such representative ‘species’ about 80 might be enumerated” (Newton, Dict. Birds, p. 335).
Of the many attempts to subdivide the Nearctic subregion, the same authority favours that of Dr S. F. Baird, who distinguishes between Canadian, Alleghanian, Middle or Missourian, Californian and Alaskan provinces. Dr Hart Merriam takes the broad point of view “that the whole of extratropical North America consists of but two primary life regions, a Boreal region, which is circumpolar, and a Sonoran or Mexican tableland region which is unique.” The first of these supports Newton’s contention of the essential unity of the Nearctic and Palaearctic areas. In any case the various Nearctic subdivisions completely merge into each other, just as is to be expected from the physical configuration and other bionomic conditions of the Nort American continent.
The Palaearctic Subregion is, broadly speaking, Europe and Asia, with the exception of India and China. The propriety of comprehending this enormous tract in one zoological “region” was first shown by Dr P. L. Sclater, and as regards the distribution of most classes of animals there have been few to doubt that it is an extremely natural one. Not indeed altogether so homogeneous as the Nearctic area, it presents, however, even at its extreme points, no very striking difference between the bulk of its birds. Though Japan is far removed from western Europe, and though a few generic forms and still fewer families inhabit the one without also frequenting the other, yet there is a most astonishing similarity in a large portion of their respective birds. In some cases the closest examination has failed to detect any distinction that may be called specific between the members of their avifauna; but in most it is possible to discover just sufficient difference to warrant a separation of the subjects. Nevertheless, it is clear that in Japan we have, as it were, a repetition of some of our most familiar species—the redbreast and the hedge-sparrow, for example—slightly modified in plumage or otherwise, so as to furnish instances of the most accurate representation, e.g. Cyanopica cooki of Portugal and Spain, and C. cyana of Amoorland and Japan.
Like the Nearctic the Palaearctic subregion seems to possess but one single peculiar family of land birds, the Panuridae, represented by the beautiful species known to Englishmen as the bearded tit-mouse, Panurus biarmicus. The entire number of Palaearctic families are, according to Newton, 67, and of the genera 323. Of these 128 are common to the Nearctic subregion. Species of 51 more seem to occur as true natives within the Ethiopian and Indian regions, and besides these 18 appear to be common to the Ethiopian without being found in the Indian, and no fewer than 71 to the Indian without occurring in the Ethiopian. To compare the Palaearctic genera with those of the Australian and Neotropical regions would be simply a waste of time, for the points of resemblance are extremely few, and such as they are they lead to nothing. It will therefore be seen from the above that next to the Nearctic are the Palaearctic has a much greater affinity to any other, a fact which might be expected from geographical considerations.
Having shown this much we have next to deal with the peculiarities of the vast Palaearctic subregion. At the lowest computation 37 genera seem to be peculiar to it, though it is certain that species of several are regularly wont to wander beyond its limits in winter seeking a southern climate. Of the peculiar genera only a few examples may be mentioned: Eurynorhynchus, the spoon-billed sandpiper of Siberia; Syrrhaptes, the sandgrouse of central Asia; Musicicapa of Europe.
We distinguish between a Siberian, Mongolian, Mediterranean and European province, none of which can be well defined. The islands of the Canaries, Madeira and the Azores belong to the Mediterranean province, and offer some peculiarities of great interest. The Azores have been monographed by F. D. Godman (Nat. Hist. of the Azores or Western Islands, London, 1870). There is a general tendency among these insular birds to vary more or less from their continental representatives, and this is especially shown by the former having always darker plumage and stronger bills and legs. In one instance the variation is so excessive that it fully justifies the establishment of a specific distinction. This is the case of the bullfinch of the more western of these islands (Pyrrhula murina), the male of which, instead of the ruddy breast of its well-known congener (P. vulgaris), has that part of a sober mouse-colour. A similar sombre hue distinguishes the peculiar chaffinch of the Canary Islands (Fringilla teydea), but to these islands as well as the Azores and Madeiras there belongs in common another chaffinch (F. tintillon) which, though very nearly allied to that of Mauritania (F. spodogenia) is perfectly recognizable, and not found elsewhere. Madeira has also its peculiar golden-crested wren (Regulus maderensis), and its peculiar pigeon (Columba trocaz), while two allied forms of the latter (C. laurivora and C. bollii) are found only in the Canaries. Further on this subject we must not go; we can only state that Godman has shown good reason for declaring that the avifauna of all these islands is the effect of colonization extending over a long period of years, and going on now.
Palaeotropical Region.—Much can be said in favour of combining the mostly tropical portion of the great mass of land of the Old World (excluding, of course, Austrogaea or the Australian region) into one region, for which Oscar Drude’s well-chosen term “palaeotropical” has been adopted (cf. Bronn’s Thierreich, System Part. p. 296, 1893). This region naturally comprises the African and Indian areas, conformably to be called subregions.
Both subregions possess, besides others, the following characteristic birds: Ratitae, viz. Struthio in Africa and Arabia, fossil also in the Sivalik Hills, and Aepyornithidae in Madagascar; Pittidae, Bucerotinae and Upupinae, of which Upupa itself in India, Madagascar and Africa; Coraciidae; Pycnonotidae or bulbuls; Trogonidae, of which the Asiatic genera are the less specialized in opposition to the Neotropical forms; Vulturidae; Leptoptilus, Anastomus and Ciconia among the storks; Pteroclidae; Treroninae among pigeons. Of other families which, however, extend their range more or less far into the Australian realm, may be mentioned Otididae, the bustards; Meropidae or bee-eaters; Muscicapidae or flycatchers; Sturnidae or starlings.
The Ethiopian Subregion comprises the whole of Africa and Madagascar, except the Barbary States, but including Arabia; in the north-east the subregion melts into the Palaearctic between its limits still farther to the eastwards, through Beluchistan and even beyond the Indus.
So large a portion of the Ethiopian subregion lies between the tropics that no surprise need be expressed at the richness of its fauna relatively to that of the last two subregions we have considered. Between fifty and sixty so-called families of land birds alone are found within its limits, and of them at least nine are peculiar; the typical genera of which are Buphaga, Euryceros, Philepitta, Musophaga, Irrisor, Leptosoma, Colius, Serpentarius, Struthio, Aepyornis. It is singular that only the first three of them belong to the order Passeriformes, a proportion which is not maintained in any other tropical region. The number of peculiar genera, besides those just mentioned, is too great for them to be named here; some of the most remarkable on the continent are: Balaeniceps, the whale-headed heron; Balaearica, the crowned crane; Podica, finfoot; Numida and allied genera of guinea fowls.
The natural division of the subregion is that into an African and a Madagascar province. Subdivision of the continental portion is beset with great difficulties, and none of the numerous attempts have proved long-lived. The forest-clad basin of the Congo, with the coastal districts of the bay of Guinea, seem to form one domain in opposition to the rest.
The Malagasy province comprises, besides Madagascar, the Mascarene, Comoro and Seyehelle islands. It may be safely deemed the most peculiar area of the earth’s surface, while from the richness and multifariousness of its animal, and especially of its ornithic population, New Zealand cannot be compared with it. In A. Grandidier’s magnificent Histoire physique, naturelle et politique de Madagascar, vol. xii. (Paris, 1875-1884), are enumerated 238 species as belonging to the island, of which 129 are peculiar to it, and among those are no fewer than 35 peculiar genera. Euryceros of the