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.
It will therefore be seen from the above that next to the Nearctic area the Palaearctic has a much greater affinity to any other, a fact which might be expected from geographical considerations.
With three exceptions, all the genera of this extensive family belong to the New World, being specially characteristic of the Neotropical region, where they occur as far south as Patagonia, while extending northward into the warmer parts of the Nearctic regions as far as California and British Columbia.
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 titmouse, Panurus biarmicus.
This is a state of things which exists nowhere else; for except in Australia, where a few indigenous and peculiar low non-Oscines are found, and in the Nearctic country, whither one family of Clamatores, viz.
Thus comparing the Nearctic and Palaearctic floras we find striking differences overlying the points of agreement already indicated.
In some cases, such as the Ethiopian and Neotropical and the Palaearctic and Nearctic regions, the faunas, although distinct, are related, several forms on opposite sides of the Atlantic being analogous, e.g.
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 of stragglers, there are about 120 common to the two 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 North American continent.
G..Gmelin, Giildenstalt, Lepechin and others - in the exploration of the recently extended Russian empire supplied not only much material to the Commentarii and Acta of the Academy of St Petersburg, but more that is to be found in their narratives - all of it being of the highest interest to students of Palaearctic or Nearctic ornithology.