Island Life; Or, The Phenomena and Causes of Insular Faunas and Floras

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

1. Accentor rubidus. Nearly allied to our hedge-sparrow, and less closely to the Central Asian A. immaculatus.

(1a. Hypsipetes amaurotis. Migrates to the Corea, otherwise peculiar.)

2. Zosterops japonica. Allied to two Chinese species.

3. Lusciniola pryeri.

4. Garrulus japonicus. Allied to the Siberian and British Jays.

5. Fringilla kawarahiba. Allied to the Chinese greenfinch.

6. Emberiza ciopsis. Allied to the E. Siberian bunting E. cioides, of which it may be considered a sub-species.

7.        ,,      yessoensis. A distinct species.

8.        ,,      personata. A sub-species of E. spodocephala.

9. Gecinus awokera. A distinct species of green woodpecker.

10. Picus namiyei. Allied to a Formosan species.

11. Treron sieboldi. Allied to T. sphenura of the Himalayas, and to a Formosan species.

12. Carpophaga ianthina. A distinct species of fruit-pigeon.

13. Bubo blakistoni. Allied to a Philippine eagle-owl.

14. Scops semitorgues. A distinct species.

15. Phasianus versicolor. A distinct species.

16.        ,,       sœmmeringi. A distinct species.

17.        ,,       scintillaus. A sub-species of the last.

The large number of seventeen peculiar species in the outlying Bonin and Loo Choo Islands is an interesting feature of Japanese ornithology. The comparative remoteness of these islands, their mild sub-tropical climate and luxuriant vegetation, and perhaps the absence of violent storms and their being situated out of the line of continental migration, seem to be the conditions that have favoured the specialisation of modified types adapted to the new environment.

Japan Birds Recurring in Distant Areas.—The most interesting feature in the ornithology of Japan is, undoubtedly, the presence of several species which indicate an alliance with such remote districts as the Himalayas, the Malay Islands, and Europe. Among the peculiar species, the most remarkable of this class are,—the fruit-pigeon of the genus Treron, entirely unknown in China, but reappearing in Formosa and Japan; the Hypsipetes, whose nearest ally is in South China at a distance of nearly 500 miles; and the jay (Garrulus japonicus), whose near ally (G. glandarius) inhabits Europe only, at a distance of 3,700 miles. But even more extraordinary are the following non-peculiar species:—Spizaetus orientalis, a crested eagle, inhabiting the Himalayas, Formosa, and Japan, but unknown in Southern or Eastern China; Ceryle guttata, a spotted kingfisher, almost confined to the Himalayas and Japan, though occurring rarely in Central China; and Halcyon coromanda, a brilliant red kingfisher inhabiting Northern India, the Malay Islands to Celebes, Formosa, and Japan. We have here an excellent illustration of the favourable conditions which islands afford both for species which elsewhere live further south (Halcyon coromanda), and for the preservation in isolated colonies of species which are verging towards extinction; for such we must consider the above-named eagle and kingfisher, both confined to a very limited area on the continent, but surviving in remote islands. Referring to our account of the birth, growth, and death of a species (in Chapter IV.) it can hardly be doubted that the Ceryle guttata formerly ranged from the Himalayas to Japan, and has now almost died out in the intervening area owing to geographical and physical changes, a subject which will be better discussed when we have examined the interesting fauna of the island of Formosa.

The other orders of animals are not yet sufficiently known to enable us to found any accurate conclusions upon them. The main facts of their distribution have already been given in my Geographical Distribution of Animals (Vol I., pp. 227-231), and they sufficiently agree with the birds and mammalia in showing a mixture of temperate and tropical forms with a considerable proportion of peculiar species. Owing to the comparatively easy passage from the northern extremity of Japan through the island of Saghalien to the mainland of Asia, a large number of temperate forms of insects and birds are still able to enter the country, and thus diminish the proportionate number of peculiar species. In the case of mammals this is more difficult; and the large proportion of specific difference in their case is a good indication of the comparatively remote epoch at which Japan was finally separated from the continent. How long ago this separation took place we cannot of course tell, but we may be sure it was much longer than in the case of our own islands, and therefore probably in the earlier portion of the Pliocene period.

Formosa

Among recent continental islands there is probably none that surpasses in interest and instructiveness the Chinese island named by the Portuguese, Formosa, or "The Beautiful." Till quite recently it was a terra incognita to naturalists, and we owe almost all our present knowledge of it to a single man, the late Mr. Robert Swinhoe, who, in his official capacity as one of our consuls in China, visited it several times between 1856 and 1866, besides residing on it for more than a year. During this period he devoted all his spare time and energy to the study of natural history, more especially of the two important groups, birds and mammals; and by employing a large staff of native collectors and hunters, he obtained a very complete knowledge of its fauna. In this case, too, we have the great advantage of a very thorough knowledge of the adjacent parts of the continent, in great part due to Mr. Swinhoe's own exertions during the twenty years of his service in that country. We possess, too, the further advantage of having the whole of the available materials in these two classes collected together by Mr. Swinhoe himself after full examination and comparison of specimens; so that there is probably no part of the world (if we except Europe, North America, and British India) of whose warm-blooded vertebrates we possess fuller or more accurate knowledge than we do of those of the coast districts of China and its islands.147

Physical Features of Formosa.—The island of Formosa is nearly half the size of Ireland, being 220 miles long, and from twenty to eighty miles wide. It is traversed down its centre by a fine mountain range, which reaches an altitude of about 8,000 feet in the south and 12,000 feet in the northern half of the island, and whose higher slopes and valleys are everywhere clothed with magnificent forests. It is crossed by the line of the Tropic of Cancer a little south of its centre; and this position, combined with its lofty mountains, gives it an unusual variety of tropical and temperate climates. These circumstances are all highly favourable to the preservation and development of animal life, and from what we already know of its productions, it seems probable that few, if any islands of approximately the same size and equally removed from a continent will be found to equal it in the number and variety of their higher animals. The outline map (at page 392) shows that Formosa is connected with the mainland by a submerged bank, the hundred-fathom line including it along with Hainan to the south-west and Japan on the north-east; while the line of two-hundred fathoms includes also the Madjico-Sima and Loo-Choo Islands, and may, perhaps, mark out approximately the last great extension of the Asiatic continent, the submergence of which isolated these islands from the mainland.

Animal Life of Formosa.—We are at present acquainted with 35 species of mammalia, and 128 species of land-birds from Formosa, fourteen of the former and forty-three of the latter being peculiar, while the remainder inhabit also some part of the continent or adjacent islands. This proportion of peculiar species is perhaps (as regards the birds) the highest to be met with in any island which can be classed as both continental and recent, and this, in all probability, implies that the epoch of separation is somewhat remote. It was not, however, remote enough to reach back to a time when the continental fauna was very different from what it is now, for we find all the chief types of living Asiatic mammalia represented in this small island. Thus we have monkeys; insectivora; numerous carnivora; pigs, deer, antelopes, and cattle among ungulata; numerous rodents, and the edentate Manis,—a very fair representation of Asiatic mammals, all being of known genera, and of species either absolutely identical with some still living elsewhere or very closely allied to them. The birds exhibit analogous phenomena, with the exception that we have here two peculiar and very interesting genera.

But besides the amount of specific and generic modification that has occurred, we have another indication of the lapse of time in the peculiar relations of a large proportion of the Formosan animals, which show that a great change in the distribution of Asiatic species must have taken place since the separation of the island from the continent. Before pointing these out it will be advantageous to give lists of the mammalia and peculiar birds of the island, as we shall have frequent occasion to refer to them.

List of the Mammalia of Formosa. (The peculiar species are printed in italics.)

  1. Macacus cyclopis. A rock-monkey more allied to M. rhesus of India than to M. sancti-johannis of South China.

  2. Pteropus formosus. A fruit-bat closely allied to the Japanese species. None of the genus are found in China.

  3. Vesperugo abramus. China.

  4. Vespertilio formosus. Black and orange Bat. China.

  5. Nyctinomus cestonii. Large-eared Bat. China, S. Europe.

  6. Talpa insularis. A blind mole of a peculiar species.

7. Sorex murinus. Musk Rat. China.

  8. Sorex sp. A shrew, undescribed.

  9. Erinaceus sp. A Hedgehog, undescribed.

10. Ursus tibetanus. The Tibetan Bear. Himalayas and North China.

11. Helictis subaurantiaca. The orange-tinted Tree Civet. Allied to H. nipalensis of the Himalayas more than to H. moschata of China.

12. Martes flavigula, var. The yellow-necked Marten. India, China.

13. Felis macroscelis. The clouded Tiger of Siam and Malaya.

14. Felis viverrina. The Asiatic wild Cat. Himalayas and Malacca.

15. Felis chinensis. The Chinese Tiger Cat. China.

16. Viverricula malaccensis. Spotted Civet. China, India.

17. Paguma larvata. Gem-faced Civet. China.

18. Sus taivanus. Allied to the wild Pig of Japan.

19. Cervulus reevesii. Reeve's Muntjac. China.

20. Cervus pseudaxis. Formosan Spotted Deer. Allied to C. sika of Japan.

21. Cervus swinhoii. Swinhoe's Rusa Deer. Allied to Indian and Malayan species.

22. Nemorhedus swinhoii. Swinhoe's Goat-antelope. Allied to the species of Sumatra and Japan.

23. Bos chinensis. South China wild Cow.

24. Mus bandicota. The Bandicoot Rat. Perhaps introduced from India.

25. Mus indicus. Indian Rat.

26. Mus coxinga. Spinous Country-rat.

27. Mus canna. Silken Country-rat.

28. Mus losca. Brown Country-rat.

29. Sciurus castaneoventris. Chestnut-bellied Squirrel. China and Hainan.

30. Sciurus m'clellandi. M‘Clelland's Squirrel. Himalayas, China.

31. Sciuropterus kaleensis. Small Formosan Flying Squirrel. Allied to S. alboniger of Nepal.

32. Pteromys grandis. Large Red Flying Squirrel. Allied to Himalayan and Bornean species. From North Formosa.

33. Pteromys pectoralis. White-breasted Flying Squirrel. From South Formosa.

34. Lepus sinensis. Chinese Hare. Inhabits South China.

35. Manis dalmanni. Scaly Ant-eater. China and the Himalayas.

The most interesting and suggestive feature connected with these Formosan mammals is the identity or affinity of several of them, with Indian or Malayan rather than with Chinese species. We have the rock-monkey of Formosa allied to the rhesus monkeys of India and Burma, not to those of South China and Hainan. The tree civet (Helictis subaurantiaca), and the small flying squirrel (Sciuropterus kaleensis), are both allied to Himalayan species. Swinhoe's deer and goat-antelope are nearest to Malayan species, as are the red and white-breasted flying squirrels; while the fruit-bat, the wild pig, and the spotted deer are all allied to peculiar Japanese species. The clouded tiger is a Malay species unknown in China, while the Asiatic wild cat is a native of the Himalayas and Malacca. It is clear, therefore, that before Formosa was separated from the mainland the above named animals or their ancestral types must have ranged over the intervening country as far as the Himalayas on the west, Japan on the north, and Borneo or the Philippines on the south; and that after that event occurred, the conditions were so materially changed as to lead to the extinction of these species in what are now the coast provinces of China, while they or their modified descendants continued to exist in the dense forests of the Himalayas and the Malay Islands, and in such detached islands as Formosa and Japan. We will now see what additional light is thrown upon this subject by an examination of the birds.

List of the Land Birds peculiar to FormosaTurdidæ (Thrushes)

1. Turdus albiceps. Allied to Chinese species.

Sylvidiæ (Warblers)

2. Cisticola volitans. Allied to C. schœnicola of India and China.

3. Herbivox cantans. Sub-species of H. cantillaus of N. China and Japan.

4. Notodela montium. Allied to N. leucura of the Himalayas; no ally in China.

Timaliidæ (Babblers)

5. Pomatorhinus musicus. Allies in S. China and the Himalayas.

6. P. erythroenemis.              Do.                  do.

7. Garrulax ruficeps. Allied to G. albogularis of N. India and East Thibet, not to the species of S. China (G. sannio).

8. Janthocincla pœcilorhyncha. Allied to J. cœrulata of the Himalayas. None of the genus in China.

9. Trochalopteron taivanus. Allied to a Chinese species.

10. Alcippe morrisoniana. Near the Himalayan A. nipalensis. None of the genus in China.

11. A. brunnea.                                        Do.                                        do.

12. Sibia auricularis. Allied to the Himalayan S. capistrata. The genus not known in China.

Panuridæ (Bearded Tits, &c.)

13. Suthora bulomachus. Allied to the Chinese S. suffusa.

Cinclidæ (Dippers and Whistling Thrushes)

14. Myiophoneus insularis. Allied to M. horsfieldi of South India.

Paridæ (Tits)

15. Parus insperatus. Sub-species of P. monticola of the Himalayas and East Thibet.

16. P. castaneiventris. Allied to P. varius of Japan.

Liotrichidæ (Hill Tits)

17. Liocichla steerii. A peculiar genus of a specially Himalayan family, quite unknown in China.

Pycnonotidæ (Bulbuls)

18. Pycnonotus (Spizixos) cinereicapillus. Very near P. semitorques of China.

19. Hypsipetes nigerrimus. Allied to H. concolor of Assam, not to H. macclellandi of China.

Oriolidæ (Orioles)

20. Analcipus ardens. Allied to A. traillii of the Himalayas and Tenasserim.

Campephagidæ (Caterpillar Shrikes)

21. Graucalus rex-pineti. Closely allied to the Indian G. macei. No ally in China.

Dicruridæ (King Crows)

22. Chaptia brauniana. Closely allied to C. ænea of Assam. No ally in China.

Muscicapidæ (Flycatchers)

23. Cyornis vivida. Allied to C. rubeculoides of India.

Corvidæ (Jays and Crows)

24. Garrulus taivanus. Allied to G. sinensis of S. China.

25. Urocissa cœrulea. A very distinct species from its Indian and Chinese allies.

26. Dendrocitta formosæ. A sub-species of the Chinese D. sinensis.

Ploceidæ (Weaver Finches)

27. Munia formosana. Allied to M. rubronigra of India and Burmah.

Alaudidæ (Larks)

28. Alauda sala. Allies in South China.

29. A. wattersi.               Do.

Pittidæ (Pittas)

30. Pitta oreas. Allied to P. cyanoptera of Malaya and S. China.

Picidæ (Woodpeckers)

31. Picus insularis. Allied to P. leuconotus of Japan and Siberia.

Megalæmidæ

32. Megalæma nuchalis. Allied to M. oortii of Sumatra and M. faber of Hainan. No allies in China.

Caprimulgidæ (Goatsuckers)

33. Caprimulgus stictomus. A sub-species of C. monticolus of India and China.

Columbidæ (Pigeons)

34. Treron formosæ. Allied to Malayan species.

35. Sphenocercus sororius. Allied to Malay species and to S. sieboldi of Japan. No allies of these two birds inhabit China.

36. Chalcophaps formosana. Allied to the Indian species which extends to Tenasserim and Hainan.

Tetraonidæ (Grouse and Partridges)

37. Orcoperdix crudigularis. A peculiar genus of partridges.

38. Bambusicola sonorivox. Allied to the Chinese B. thoracica.

39. Arcoturnix rostrata. Allied to the Chinese A. blakistonii.

Phasianidæ (Pheasants)

40. Phasianus formosanus. Allied to P. torquatus of China.

41. Euplocamus swinhoii. A very peculiar and beautiful species allied to the tropical fire-backed pheasants, and to the silver pheasant of North China.

Strigidæ (Owls)

42. Athene pardalota. Closely allied to a Chinese species.

43. Lempigius hambroekii. Allied to a Chinese species.

This list exhibits to us the marvellous fact that more than half the peculiar species of Formosan birds have their nearest allies in such remote regions as the Himalayas, South India, the Malay Islands, or Japan, rather than in the adjacent parts of the Asiatic continent. Fourteen species have Himalayan allies, and six of these belong to genera which are unknown in China. One has its nearest ally in the Nilgherries, and five in the Malay Islands; and of these six, four belong to genera which are not Chinese. Two have their only near allies in Japan. Perhaps more curious still are those cases in which, though the genus is Chinese, the nearest allied species is to be sought for in some remote region. Thus we have the Formosan babbler (Garrulax ruficeps) not allied to the species found in South China, but to one inhabiting North India and East Thibet; while the black bulbul (Hypsipetes nigerrimus), is not allied to the Chinese species but to an Assamese form.

In the same category as the above we must place eight species not peculiar to Formosa, but which are Indian or Malayan rather than Chinese, so that they offer examples of discontinuous distribution somewhat analogous to what we found to occur in Japan. These are enumerated in the following list.

Species of Birds common to Formosa and India or Malaya, but not found in China

1. Siphia superciliaris. The Rufous-breasted Flycatcher of the S. E. Himalayas.

2. Halcyon coromanda. The Great Red Kingfisher of India, Malaya, and Japan.

3. Palumbus pulchricollis. The Darjeeling Wood-pigeon of the S. E. Himalayas.

4. Turnix dussumieri. The larger Button-quail of India.

5. Spizaetus nipalensis. The Spotted Hawk-eagle of Nepal and Assam.

6. Lophospiza trivirgata. The Crested Gos-hawk of the Malay Islands.

7. Bulaca newarensis. The Brown Wood-owl of the Himalayas.

8. Strix candida. The Grass-owl of India and Malaya.

The most interesting of the above are the pigeon and the flycatcher, both of which are, so far as yet known, strictly confined to the Himalayan mountains and Formosa. They thus afford examples of discontinuous specific distribution exactly parallel to that of the great spotted kingfisher, already referred to as found only in the Himalayas and Japan.

Comparison of the Faunas of Hainan, Formosa, and Japan.—The island of Hainan on the extreme south of China, and only separated from the mainland by a strait fifteen miles wide, appears to have considerable similarity to Formosa, inasmuch as it possesses seventeen peculiar land-birds (out of 130 obtained by Mr. Swinhoe), two of which are close allies of Formosan species, while two others are identical. We also find four species whose nearest allies are in the Himalayas. Our knowledge of this island and of the adjacent coast of China is not yet sufficient to enable us to form an accurate judgment of its relations, but it seems probable that it was separated from the continent at, approximately, the same epoch as Formosa and Japan, and that the special features of each of these islands are mainly due to their geographical position. Formosa, being more completely isolated than either of the others, possesses a larger proportion of peculiar species of birds, while its tropical situation and lofty mountain ranges have enabled it to preserve an unusual number of Himalayan and Malayan forms. Japan, almost equally isolated towards the south, and having a much greater variety of climate as well as a much larger area, possesses about an equal number of mammalia with Formosa, and an even larger proportion of peculiar species. Its birds, however, though more numerous are less peculiar; and this is probably due to the large number of species which migrate northwards in summer, and find it easy to enter Japan through the Kurile Isles or Saghalien.148 Japan too, is largely peopled by those northern types which have an unusually wide range, and which, being almost all migratory, are accustomed to cross over seas of moderate extent. The regular or occasional influx of these species prevents the formation of special insular races, such as are almost always produced when a portion of the population of a species remains for a considerable time completely isolated. We thus have explained the curious fact, that while the mammalia of the two islands are almost equally peculiar, (those of Japan being most so in the present state of our knowledge), the birds of Formosa show a far greater number of peculiar species than those of Japan.