be best understood when we have examined the corresponding affinities of the birds of Japan.
Birds.—Owing to the recent researches of some English residents we have probably a fuller knowledge of the birds than of the mammalia; yet the number of true land-birds ascertained to inhabit the islands either as residents or migrants is only 200, which is less than might be expected considering the highly favourable conditions of mild climate, luxuriant vegetation, and abundance of insect-life, and the extreme riches of the adjacent continent,—Mr. Swinhoe's list of the birds of China containing more than 400 land species, after deducting all which are peculiar to the adjacent islands. Only seventeen species, or about one-twelfth of the whole, are now considered to be peculiar to Japan proper; while seventeen more are peculiar to the various outlying small islands constituting the Bonin and Loo Choo groups. Even of these, six or seven are classed by Mr. Seebohm as probably sub-species or slightly modified forms of continental birds, so that ten only are well-marked species, undoubtedly distinct from those of any other country.
The great majority of the birds are decidedly temperate forms identical with those of Northern Asia and Europe; while no less than forty of the species of land-birds are also found in Britain, or are such slight modifications of British species that the difference is only perceptible to a trained ornithologist. The following list of the land-birds common to Britain and Japan is very interesting, when we consider that these countries are separated by the whole extent of the European and Asiatic continents, or by almost exactly one-fourth of the circumference of the globe:—
Land Birds Common to Great Britain and Japan.[[146]]
(Either Identical Species or Representative sub-species.)
But even these fifty-three species by no means fairly represent the amount of resemblance between Britain and
Japan as regards birds; for there are also thrushes, robins, stonechats, wrens, hedge-sparrows, sedge-warblers, jays, starlings, swifts, goatsuckers, and some others, which, though distinct species from our own, have the same general appearance, and give a familiar aspect to the ornithology. There remains, however, a considerable body of Chinese and Siberian species, which link the islands to the neighbouring parts of the continent; and there are also a few which are Malayan or Himalayan rather than Chinese, and thus afford us an interesting problem in distribution.
The seventeen species and sub-species which are altogether peculiar to Japan proper, are for the most part allied to birds of North China and Siberia, but three are decidedly tropical, and one of them—a fruit pigeon (Treron sieboldi)—has no close ally nearer than Burmah and the Himalayas. In the following list the affinities of the species are indicated wherever they have been ascertained:—
List of the Species of Land Birds Peculiar To Japan.