antennæ and legs, varied in form and structure in an endless
variety of ways, and adorned with equally varied colours, spots
and markings. Some are large and massive insects three or four
inches long, while others are no bigger than our smaller ants. The
majority have sober colours, but often delicately marbled, veined,
or spotted; while others are red, or blue, or yellow, or adorned
with the richest metallic tints. Their antennæ are sometimes
excessively long and graceful, often adorned with tufts of hair,
and sometimes pectinated. They especially abound where timber
trees have been recently felled in the primeval forests; and while
extensive clearings are in progress their variety seems endless.
In such a locality in the island of Borneo, nearly 300 different
species were found during one dry season, while the number obtained
during eight years’ collecting in the whole Malay Archipelago was
about a thousand species.
Among the beetles that always attract attention in the tropics
are the large, horned, Copridæ and Dynastidæ, corresponding to
our dung-beetles. Some of these are of great size, and they are
occasionally very abundant. The immense horn-like protuberances on
the head and thorax of the males in some of the species are very
extraordinary, and, combined with their polished or rugose metallic
colours, render them perhaps the most conspicuous of all the beetle
tribe. The weevils and their allies are also very interesting, from
their immense numbers, endless variety, and the extreme beauty of
many of the species. The Anthribidæ, which are especially abundant
in the Malay Archipelago, rival the Longicorns in the immense
length of their elegant antennæ; while the diamond beetles of
Brazil, the Eupholi of the Papuan islands, and the Pachyrhynchi of
the Philippines, are veritable living jewels.
Where a large extent of virgin forest is cut down in the early
part of the dry season, and some hot sunny weather follows, the
abundance and variety of beetles attracted by the bark and foliage
in various stages of drying is amazing. The air is filled with the
hum of their wings. Golden and green Buprestidæ are flying about in
every direction, and settling on the bark in full sunshine. Green
and spotted rose-chafers hum along near the ground; long-horned
Anthribidæ are disturbed at every step; elegant little Longicorns
circle about the drying foliage, while larger species fly slowly
from branch to branch. Every fallen trunk is full of life. Strange
mottled, and spotted, and rugose Longicorns, endless Curculios,
queer-shaped Brenthidæ, velvety brown or steel-blue Cleridæ, brown or
yellow or whitish click beetles, (Elaters), and brilliant metallic
Carabidæ. Close by, in the adjacent forest, a whole host of new forms
are found. Elegant tiger-beetles, leaf-hunting Carabidæ, musk-beetles
of many sorts, scarlet Telephori, and countless Chrysomelas Hispas,
Coccinellas, with strange Heteromera, and many curious species which
haunt fungi, rotten bark or decaying leaves. With such variety and
beauty the most ardent entomologist must be fully satisfied; and
when, every now and then, some of the giants of the tropics fall in
his way--grand Prionidæ or Lamiidæ several inches long, a massive
golden Buprestis, or a monster horned Dynastes--he feels that his
most exalted notions of the insect-life of the tropics are at length
realized.
_Wingless Insects._--Passing on to other orders of insects, the
hemiptera, dragon-flies, and true flies hardly call for special
remark. Among them are to be found a fair proportion of large and
handsome species, but they require much searching after in their
special haunts, and seldom attract so much attention as the groups
of insects already referred to. More prominent are the wingless
tribes, such as spiders, scorpions, and centipedes. The wanderer
in the forests often finds the path closed by large webs almost as
strong as silk, inhabited by gorgeous spiders with bodies nearly two
inches long and legs expanding six inches. Others are remarkable
for their hard flat bodies, terminating in horned processes which
are sometimes long, slender, and curved like a pair of miniature
cow’s horns. Hairy terrestrial species of large size are often met
with, the largest belonging to the South American genus Mygale,
which sometimes actually kill birds, a fact which had been stated
by Madame Merian and others, but was discredited till Mr. Bates
succeeded in catching one in the act. The small jumping spiders are
also noticeable from their immense numbers, variety, and beauty.
They frequent foliage and flowers, running about actively in pursuit
of small insects; and many of them are so exquisitely coloured as
to resemble jewels rather than spiders. Scorpions and centipedes
make their presence known to every traveller. In the forests of
the Malay islands are huge scorpions of a greenish colour and
eight or ten inches long; while in huts and houses smaller species
lurk under boxes and boards, or secrete themselves in almost every
article not daily examined. Centipedes of immense size and deadly
venom harbour in the thatch of houses and canoes, and will even
ensconce themselves under pillows and in beds, rendering a thorough
examination necessary before retiring to rest. Yet with moderate
precautions there is little danger from these disgusting insects,
as may be judged by the fact that during twelve years wanderings
in American and Malayan forests the author was never once bitten
or stung by them.
_General Observations on Tropical Insects._--The characteristics of
tropical insects that will most attract the ordinary traveller, are,
their great numbers, and the large size and brilliant colours often
met with. But a more extended observation leads to the conclusion
that the average of size is probably no greater in tropical than
in temperate zones, and that, to make up for a certain proportion
of very large, there is a corresponding increase in the numbers of
very small species. The much greater size reached by many tropical
insects is no doubt due to the fact, that the supply of food is
always in excess of their demands in the larva state, while there
is no check from the ever-recurring cold of winter; and they are
thus able to acquire the dimensions that may be on the whole most
advantageous to the race, unchecked by the annual or periodical
scarcities which in less favoured climates would continually threaten
their extinction. The colours of tropical insects are, probably, on
the average more brilliant than those of temperate countries, and
some of the causes which may have led to this have been discussed
in another part of this volume.[11] It is in the tropics that we
find most largely developed, whole groups of insects which are
unpalatable to almost all insectivorous creatures, and it is among
these that some of the most gorgeous colours prevail. Others
obtain protection in a variety of ways; and the amount of cover or
concealment always afforded by the luxuriant tropical vegetation is
probably a potent agent in permitting a full development of colour.
[11] Chapters V. and VI.--_The Colours of Animals and Plants._
_Birds._--Although the number of brilliantly-coloured birds in
almost every part of the tropics is very great, yet they are by no
means conspicuous; and as a rule they can hardly be said to add
much to the general effect of equatorial scenery. The traveller is
almost always disappointed at first with the birds, as he is with
the flowers and the beetles; and it is only when, gun in hand, he
spends days in the forest, that he finds out how many beautiful
living things are concealed by its dense foliage and gloomy thickets.
A considerable number of the handsomest tropical birds belong to
family groups which are confined to one continent with its adjacent
islands; and we shall therefore be obliged to deal for the most
part with such large divisions as tribes and orders, by means of
which to define the characteristics of tropical bird-life. We find
that there are three important orders of birds which, though by no
means exclusively tropical, are yet so largely developed there in
proportion to their scarcity in extra-tropical regions, that more
than any others they serve to give a special character to equatorial
ornithology. These are the Parrots, the Pigeons, and the Picariæ,
to each of which groups we will devote some attention.
_Parrots._--The parrots, forming the order Psittaci of naturalists,
are a remarkable group of fruit-eating birds, of such high and
peculiar organization that they are often considered to stand at the
head of the entire class. They are pre-eminently characteristic
of the intertropical zone, being nowhere absent within its limits
(except from absolutely desert regions), and they are generally
so abundant and so conspicuous as to occupy among birds the place
assigned to butterflies among insects. A few species range far
into the temperate zones. One reaches Carolina in North America,
another the Magellan Straits in South America; in Africa they only
extend a few degrees beyond the southern tropic; in North-Western
India they reach 35° North Latitude; but in the Australian region
they range farthest towards the pole, being found not only in New
Zealand, but as far as the Macquarie Islands in 54° South, where
the climate is very cold and boisterous, but sufficiently uniform
to supply vegetable food throughout the year. There is hardly any
part of the equatorial zone in which the traveller will not soon
have his attention called to some members of the parrot tribe. In
Brazil, the great blue and yellow or crimson macaws may be seen every
evening wending their way homeward in pairs, almost as commonly as
rooks with us; while innumerable parrots and parraquets attract
attention by their harsh cries when disturbed from some favourite
fruit-tree. In the Moluccas and New Guinea, white cockatoos and
gorgeous lories in crimson and blue, are the very commonest of
birds.
No group of birds--perhaps no other group of animals--exhibits
within the same limited number of genera and species, so wide a
range and such an endless variety of colour. As a rule parrots may
be termed green birds, the majority of the species having this
colour as the basis of their plumage relieved by caps, gorgets,
bands and wing-spots of other and brighter hues. Yet this general
green tint sometimes changes into light or deep blue, as in some
macaws; into pure yellow or rich orange, as in some of the American
macaw-parrots (_Conurus_); into purple, grey, or dove-colour, as
in some American, African, and Indian species; into the purest
crimson, as in some of the lories; into rosy-white and pure white,
as in the cockatoos; and into a deep purple, ashy or black, as in
several Papuan, Australian, and Mascarene species. There is in
fact hardly a single distinct and definable colour that cannot be
fairly matched among the 390 species of known parrots. Their habits,
too, are such as to bring them prominently before the eye. They
usually feed in flocks; they are noisy, and so attract attention;
they love gardens, orchards, and open sunny places; they wander
about far in search of food, and towards sunset return homewards
in noisy flocks, or in constant pairs. Their forms and motions are
often beautiful and attractive. The immensely long tails of the
macaws, and the more slender tails of the Indian parraquets; the
fine crest of the cockatoos; the swift flight of many of the smaller
species, and the graceful motions of the little love-birds and
allied forms; together with their affectionate natures, aptitude
for domestication, and powers of mimicry--combine to render them
at once the most conspicuous and the most attractive of all the
specially tropical forms of bird-life.
The number of species of parrots found in the different divisions
of the tropics is very unequal. Africa is by far the poorest;
since along with Madagascar and the Mascarene islands, which have
many peculiar forms, it scarcely numbers two dozen species. Asia,
along with the Malay islands as far as Java and Borneo, is also
very poor, with about thirty species. Tropical America is very much
richer, possessing about 140 species, among which are many of the
largest and most beautiful forms. But of all parts of the globe the
tropical islands belonging to the Australian region (from Celebes
eastward), together with the tropical parts of Australia, are richest
in the parrot tribe, possessing about 150 species, among which are
many of the most remarkable and beautiful of the entire group. The
whole Australian region, whose extreme limits may be defined by
Celebes, the Marquesas, and the New Zealand group, possesses about
200 species of parrots.
_Pigeons._--These are such common birds in all temperate countries,
that it may surprise many readers to learn that they are nevertheless
a characteristic tropical group. That such is the case, however,
will be evident from the fact that only sixteen species are known
from the whole of the temperate parts of Europe, Asia, and North
America, while about 330 species inhabit the tropics. Again,
the great majority of the species are found congregated in the
equatorial zone, whence they diminish gradually toward the limits
of the tropics, and then suddenly fall off in the temperate zones.
Yet although they are pre-eminently tropical or even equatorial
as a group, they are not, from our present point of view, of much
importance, because they are so shy and so generally inconspicuous
that in most parts of the tropics an ordinary observer might
hardly be aware of their existence. The remark applies especially
to America and Africa, where they are neither very abundant nor
peculiar; but in the Eastern hemisphere, and especially in the
Malay Archipelago and Pacific islands, they occur in such profusion
and present such singular forms and brilliant colours, that they
are sure to attract attention. Here we find the extensive group
of fruit-pigeons, which, in their general green colours adorned
with patches and bands of purple, white, blue, or orange, almost
rival the parrot tribe; while the golden-green Nicobar pigeon, the
great crowned pigeons of New Guinea as large as turkeys, and the
golden-yellow fruit-dove of the Fijis, can hardly be surpassed for
beauty.
Pigeons are especially abundant and varied in tropical archipelagoes;
so that if we take the Malay and Pacific islands, the Madagascar
group, and the Antilles or West Indian islands, we find that they
possess between them more different kinds of pigeons than all the
continental tropics combined. Yet further, that portion of the Malay
Archipelago east of Borneo, together with the Pacific islands, is
exceptionally rich in pigeons; and the reason seems to be that
monkeys and all other arboreal mammals that devour eggs are entirely
absent from this region. Even in South America pigeons are scarce
where monkeys are abundant, and _vice versâ_; so that here we seem
to get a glimpse of one of the curious interactions of animals on
each other, by which their distribution, their habits, and even
their colours may have been influenced; for the most conspicuous
pigeons, whether by colour or by their crests, are all found in
countries where they have the fewest enemies.
_Picariæ._--The extensive and heterogeneous series of birds now
comprised under this term, include most of the fissirostral and
scansorial groups of the older naturalists. They may be described as,
for the most part, arboreal birds, of a low grade of organization,
with weak or abnormally developed feet, and usually less active than
the true Passeres or perching birds, of which our warblers, finches,
and crows may be taken as the types. The order Picariæ comprises
twenty-five families, some of which are very extensive. All are
either wholly or mainly tropical, only two of the families--the
woodpeckers and the kingfishers--having a few representatives which
are permanent residents in the temperate regions; while our summer
visitor, the cuckoo, is the sole example in Northern Europe of one
of the most abundant and widespread tropical families of birds.
Only four of the families have a general distribution over all the
warmer countries of the globe--the cuckoos, the kingfishers, the
swifts, and the goatsuckers; while two others--the trogons and the
woodpeckers--are only wanting in the Australian region, ceasing
suddenly at Borneo and Celebes respectively.
_Cuckoos._--Whether we consider their wide range, their abundance
in genera and species, or the peculiarities of their organization,
the cuckoos may be taken as the most typical examples of this
extensive order of birds; and there is perhaps no part of the tropics
where they do not form a prominent feature in the ornithology
of the country. Their chief food consists of soft insects, such
as caterpillars, grasshoppers, and the defenceless stick- and
leaf-insects; and in search after these they frequent the bushes and
lower parts of the forest, and the more open tree-clad plains. They
vary greatly in size and appearance, from the small and beautifully
metallic golden-cuckoos of Africa, Asia, and Australia, no larger
than sparrows, to the pheasant-like ground cuckoo of Borneo, the
Scythrops of the Moluccas which almost resembles a hornbill, the
Rhamphococcyx of Celebes with its richly-coloured bill, and the
Goliath cuckoo of Gilolo with its enormously long and ample tail.
Cuckoos, being invariably weak and defenceless birds, conceal
themselves as much as possible among foliage or herbage; and as a
further protection many of them have acquired the coloration of
rapacious or combative birds. In several parts of the world cuckoos
are coloured exactly like hawks, while some of the small Malayan
cuckoos closely resemble the pugnacious drongo-shrikes.
_Trogons, Barbets, and Toucans._--Many of the families of Picariæ
are confined to the tropical forests, and are remarkable for their
varied and beautiful colouring. Such are the trogons of America,
Africa, and Malaya, whose dense puffy plumage exhibits the purest
tints of rosy-pink, yellow, and white, set off by black heads and
a golden-green or rich brown upper surface. Of more slender forms,
but hardly less brilliant in colour, are the jacamars and motmots
of America, with the bee-eaters and rollers of the East, the latter
exhibiting tints of pale blue or verditor-green, which are very
unusual. The barbets are rather clumsy fruit-eating birds, found
in all the great tropical regions except that of the Austro-Malay
islands; and they exhibit a wonderful variety as well as strange
combinations of colours. Those of Asia and Malaya are mostly
green, but adorned about the head and neck with patches of the
most vivid reds, blues, and yellows, in endless combinations. The
African species are usually black or greenish-black, with masses
of intense crimson, yellow, or white, mixed in various proportions
and patterns; while the American species combine both styles of
colouring, but the tints are usually more delicate, and are often
more varied and more harmoniously interblended. In the Messrs.
Marshall’s fine work[12] all the species are described and figured;
and few more instructive examples can be found than are exhibited
in their beautifully-coloured plates, of the endless ways in which
the most glaring and inharmonious colours are often combined in
natural objects with a generally pleasing result.
[12] _A Monograph of the Capitonidæ or Scansorial Barbets_, by C.
F. T. Marshall and G. F. L. Marshall. 1871.
We will next group together three families which, although quite
distinct, may be said to represent each other in their respective
countries,--the toucans of America, the plantain-eaters of Africa,
and the hornbills of the East--all being large and remarkable birds
which are sure to attract the traveller’s attention. The toucans are
the most beautiful, on account of their large and richly-coloured
bills, their delicate breast-plumage, and the varied bands of
colour with which they are often adorned. Though feeding chiefly on
fruits, they also devour birds’ eggs and young birds; and they are
remarkable for the strange habit of sleeping with the tail laid flat
upon their backs, in what seems a most unnatural and inconvenient
position. What can be the use of their enormous bills has been
a great puzzle to naturalists, the only tolerably satisfactory
solution yet arrived at being that suggested by Mr. Bates,--that
it simply enables them to reach fruit at the ends of slender twigs
which, owing to their weight and clumsiness, they would otherwise be
unable to obtain. At first sight it appears very improbable that so
large and remarkable an organ should have been developed for such
a purpose; but we have only to suppose that the original toucans
had rather large and thick bills, not unlike those of the barbets
(to which group they are undoubtedly allied), and that as they
increased in size and required more food, only those could obtain
a sufficiency whose unusually large beaks enabled them to reach
furthest. So large and broad a bill as they now possess would not
be required; but the development of the bill naturally went on as
it had begun, and, so that it was light and handy, the large size
was no disadvantage if length was obtained. The plantain-eaters of
Africa are less remarkable birds, though adorned with rich colours
and elegant crests. The hornbills, though less beautiful than the
toucans, are more curious, from the strange forms of their huge
bills, which are often adorned with ridges, knobs, or recurved
horns. They are bulky and heavy birds, and during flight beat the
air with prodigious force, producing a rushing sound very like the
puff of a locomotive, and which can sometimes be heard a mile off.
They mostly feed on fruits; and as their very short legs render
them even less active than the toucans, the same explanation may
be given of the large size of their bills, although it will not
account for the curious horns and processes from which they derive
their distinctive name. The largest hornbills are more than four
feet long, and their laboured noisy flight and huge bills, as well
as their habits of perching on the top of bare or isolated trees,
render them very conspicuous objects.
The Picariæ comprise many other interesting families; as, for
example, the puff-birds, the todies, and the humming-birds; but
as these are all confined to America we can hardly claim them as
characteristic of the tropics generally. Others, though very abundant
in the tropics, like the kingfishers and the goatsuckers, are too
well known in temperate lands to allow of their being considered as
specially characteristic of the equatorial zone. We will therefore
pass on to consider what are the more general characteristics of the
tropical as compared with the temperate bird-fauna, especially as
exemplified among the true perchers or Passeres, which constitute
about three-fourths of all terrestrial birds.