to these examples, it is obvious that the rapid increase
of English-speaking populations in the United States and in
Australia is far greater than can be explained by immigration,
and shows two conspicuous examples of acclimatization.
On the whole, we seem justified in concluding that, under
favourable conditions, and with a proper adaptation of means
to the end in view, man may become acclimatized with at
least as much certainty and rapidity (counting by generations
rather than by years) as any of the lower animals. The
greatest difficulty in his way is not temperature, but the
presence of parasitic diseases to resist which his body has
not been prepared, and modern knowledge is rapidly defining
these dangers and the modes of avoiding them. (A. R. W.)
APPENDIX The task of collecting information as to animals
which have become permanently naturalized away from their native
haunts is anything but easy, as few regular records have been
kept by acclimatizers. Moreover, recorders of local fauna
have been almost unanimous in ignoring the introduced forms,
except when they have had occasion to comment on the effects,
real or supposed, of these immigrants on aboriginal faunas.
Mammals.---It is unnecessary here to dwell upon the world-wide
distribution of the two rats Mus rattus and M. decumanus,
and of the house-mouse M. musculus; their introduction has
always been involuntary. Similarly nearly all our domestic
mammals except the sheep have become feral somewhere or other,
whether by intentional liberation or by escape; but the smaller
ones more than the larger, such as pigs, goats, dogs and
cats. This has been especially the case in Hawaii and New
Zealand; in America, Australia and Hawaii, horses and cattle
are also feral. Feral pigs are numerous in New Zealand.
The domestic Indian buffalo (Bos bubalus) exists as
a wild animal in North Australia; it is very liable to
revert to a wild state, being little altered from its
still-existing wild ancestor. A more curious case is that
of the one-humped camel (Camelus dromedarius), a beast
only known in domestication, and that in arid countties;
yet a number of these have become feral in the Spanish
marshes, where they wade about like quadrupedal flamingoes.
The red deer (Cervus elaphus) is now widely distributed as
a wild animal over New Zealand, where also the fallow-deer
(C. dama) and the Indian sambar (C. aristotelis or
unicolor) have been introduced locally. The sambar, or one
or other of its subspecies, has also been naturalized in
Mauritius, and in the Marianne Islands in the open Pacific.
The wide introduction of the rabbit, as a wild animal, is well
known. Amounting to a serious pest in Australasian colonies, it
is also established in the Falklands and Kerguelen; its presence
in much of Europe is attributed to early acclimatization, as it
seems anciently to have been confined to the Iberian peninsula.
The hare has been established in New Zealand and Barbadoes.
Few other rodents have been designedly naturalized, but
the North American grey squirrel (Sciurus einereus)
appears to be established as a wild animal in Woburn Park,
Bedfordshire, England, and may probably spread thence.
To check the increase of the rabbit, stoats, weasels and
polecats (the last in the form of the domesticated ferret)
were introduced into New Zealand on a very large scale in the
last quarter of the 19th century. They have spread widely,
and have not confined their depredations to the rabbits, so
that the indigenous flightless birds have suffered largely.
Another carnivore of very similar habits, the Indian mongoose
(Herpestus griseus or H. mungo), has been naturalized
in Jamaica, whence it has been carried to other West Indian
Islands, and in the Hawaiian group. It has also been tried,
but unsuccessfully, in Australia. The first introduction
into Jamaica took place in 1872, and ten years later the
animal was credited with saving many thousands of pounds
annually by its destruction of rats. But before an equal
space of time had further elapsed, it had itself become
a pest; the most recent information, however, is to the
effect that its numbers are now on the decline, and that
the disturbed faunal equilibrium is being readjusted.
The civets, being celebrated for their odoriferous secretion,
are likely animals to have been naturalized. W. T. Blanford
(Fauna of British India, ``Mammals'') thinks that the presence
of the Indian form, Viverricula malaccensis, in Socotra, the
Comoro Islands and Madagascar is due to the assistance of man.
The common fox of Europe has been introduced into Australia,
where it is destructive to the native fauna and to lambs.
Among primates, a Ceylonese monkey (Macacus pileatus)
has been naturalized in Mauritius for centuries,
the circumstances of introduction being unknown.
The Common Australian ``opossum'' or phalanger (Trichosurus
vulpecula) has been naturalized in New Zealand, although very
destructive to fruit trees; the value of its fur being probably the
motive. It is said that the pelage of the New Zealand specimens
is superior, as might be expected from the colder climate.
Birds.---The introduction of mammals has been largely
influenced by economic conditions, when, indeed, it was
not absolutely accidental and unavoidable; but in the case
of birds it has been more gratuitous, so to speak, in many
cases, and hence is looked upon with especial dislike by
naturalists. The domestic birds have comparatively seldom
become feral, doubtless, as C. Darvdn points out, from the
reduction of their powers of flight in many cases. The
guinea-fowl, however, has long been in this condition in Jamaica
and St Helena, and the fowl in Hawaii and other Polynesian
islands. The pheasant has been naturalized in the United
States, New Zealand, Hawaii and St Helena. Its naturalization
in western Europe is very ancient, but the race supposed to
have been introduced by the Romans (Phasianus colchicus)
has been much modified within the last century or two by the
introduction of the ring-necked Chinese form (P. torquatus),
which produces fertile hybrids with the old breed. Thus
those acclimatized were usually, no doubt, of mixed blood,
and further introductions of pure Chinese stock have tended to
make the latter the dominant form, at any rate in the United
States (where it is erroneously called Mongolian1) and in New
Zealand. In Hawaii and St Helena the ring-neck appears to
have been the only pheasant introduced pure, but in the former
the Japanese race (P. versicolor) is also naturalized.
1 The true Mongolian pheasant (P. mongolicus), a very
different bird, has recently been introduced into England.
The golden pheasant (Chrysolophus pietus) is locally
established in the United States, as appear to be other pheasants
of less common species. The Reeves' pheasant (P. reevesi)
is at large on some English estates. Of the partridges,
the continental red-leg (Caccabis rnfo) is established in
England, and its ally, the Asiatic chukore (C. chukar), in St
Helena, as is the Californian quail (Lophortyx californica )
in New Zealand and Hawaii. The latter, however, though thriving
as an aviary bird, has failed at large in England, as did the
bob-white (Ortyx virginianus) both there and in New Zealand.
The desirable character of the grouse as game-birds has led to
many attempts at their acclimatization, but usually these have been
unsuccessful; the red grouse (Lagopus scoticus), however, the
only endemic British bird, is naturalized in some parts of Europe.
Of waterfowl, the Canada goose (Brantd eanadensis)
is naturalized to a small extent in Britain, and also,
to a less degree, the Egyptian goose (Chenalopex
aegyptiacus); the latter bird also occurs wild in New
Zealand. The modern presence of the black swan of Australia
(Chenopis atrata) in New Zealand appears to be due to
a natural irruption of the species about half a century
ago as much as to acclimatization by man, if not more so.
Birds of prey are, unjustly enough, regarded with so little
favour that few attempts have been made to naturalize
them; the continental little owl (Athene noctua),
however, has for some time been well established in
England, where it has hardly, if ever, appeared naturally.
Pigeons have been very little naturalized; the tame bird has
become feral locally in various countries, and the Chinese
turtledove (Turtur chinensis) is established in Hawaii, as is
the small East Indian zebra dove (Geopelia striata) in the
Seychelles, and the allied Australian (G. tranquilla) in St
Helena. There has also been very little naturalization of
parrots, but the rosella parrakeet of Australia (Platycercus
eximius) is being propagated by escaped captives in the
north island of New Zealand, and its ally the mealy rosella
(P. pallidiceps) is locally wild in Hawaii, the stock in
this case having descended from a single pair intentionally
liberated. Attempts to naturalize that well-known Australian
grass-parrakeet the budgerigar (Melopsittacus undulatus) in
England have so far proved abortive, and none of the species
experimented with in Norfolk and Bedfordshire effected a
settlement. The greyheaded love-bird (Agapornis cana)
of Madagascar is established in the Seychelles. Some of
the passerine birds have been the most widely distributed,
especially the house-sparrow (Passer domesticus), which is
now an integral, and very troublesome, part of the fauna in
the Australasian States and in North America. It is, in fact,
as notorious an example of over-successful acclimatization as
the rabbit, but in Hutton and Drummond's recent work on the
New Zealand animals (London, 1905) it is not regarded in this
light, considering that some very common exotic birds were needed
to keep down the insects, which it certainly did. Even in the
United States also, it has been found a useful destroyer of
weed-seeds. The house-sparrow is also feral in Argentina,
some of the West Indian islands, Hawaii and the Andamans.
The allied tree-sparrow (P. montanus) has been
locally naturalized in the United States; it is a more
desirable bird, being less prolific and pugnacious,
but it is expelled from towns by the house-sparrow.
The so-called Java sparrow (Munia orysivora), although
a destructive bird to rice, has been widely distributed
by accident or design, and is now found in several East
Indian islands besides Java, in south China, St Helena,
India, Zanzibar and the east African coast. An allied but
much smaller weaver-finch, a form of the spice-bird (Munia
nisoria punctata), is introduced and well distributed over
the Hawaiian islands. The little rooibek of South Africa
(Estrilda astrild) has been so long and well established
in St Helena that it is known in the bird trade as the St
Helena waxbill, and the brilliant scarlet weaver of Madagascar
(Fondia madagascariensis) inhabits as an imported bird
Mauritius, the Seychelles and even the remote Chagos Islands.
Returning to the true finches, the only one which can compete
with the house-sparrow in the extent of its distribution by
man is the goldfinch (Carduelis carduelis), now established
all over New Zealand, as well as in Australia, the United
States and Jamaica. It bears a good character, and is one
of the marked successes of naturalization. The redpoll
(Acanthis linaria), chaffinch (Fringilla coelebs)
and greenfinch (Chloris chloris) are established in New
Zealand, the last named being a pest there, as is also
the cirl-bunting (Emberiza cirlus)---the yellow-hammer
(E. citrinella) being perhaps confused with this also.
