The Naturalist in La Plata
by
W. H. Hudson
Part 3 out of 5
marked, might be looked on as a bird of prey.
The flesh-fly laying its eggs on the carrion-flower is only a striking
instance of the mistakes all instincts are liable to, never more
markedly than in the inherited tendency to fits of frenzied excitement:
the feeling is frequently excited by the wrong object, and explodes at
inopportune moments.
CHAPTER XIII.
NATURE'S NIGHT LIGHTS.
_(Remarks about Fireflies and other matters.)_
It was formerly supposed that the light of the firefly (in any family
possessing the luminous power) was a safeguard against the attacks of
other insects, rapacious and nocturnal in their habits. This was Kirby
and Spence's notion, but it might just as well be Pliny's for all the
attention it would receive from modern entomologists: just at present
any observer who lived in the pre-Darwin days is regarded as one of the
ancients. The reasons given for the notion or theory in the celebrated
_Introduction to Entomology_ were not conclusive; nevertheless it was
not an improbable supposition of the authors'; while the theory which
has taken its place in recent zoological writings seems in every way
even less satisfactory.
Let us first examine the antiquated theory, as it must now be called. By
bringing a raptorial insect and a firefly together, we find that the
flashing light of the latter does actually scare away the former, and is
therefore, for the moment, a protection as effectual as the camp-fire
the traveller lights in a district abounding with beasts of prey.
Notwithstanding this fact, and assuming that we have here the whole
reason of the existence of the light-emitting power, a study of the
firefly's habits compels us to believe that the insect would be just as
well off without the power as with it. Probably it experiences some
pleasure in emitting flashes of light during its evening pastimes, but
this could scarcely be considered an advantage in its struggle for
existence, and it certainly does not account for the possession of the
faculty.
About the habits of Pyrophorus, the large tropical firefly which has the
seat of its luminosity on the upper surface of the thorax, nothing
definite appears to be known; but it has been said that this instinct is
altogether nocturnal. The Pyrophorus is only found in the sub-tropical
portion of the Argentine country, and I have never met with it. With the
widely-separated Cratomorphus, and the tortoise-shaped Aspisoma, which
emit the light from the abdomen, I am familiar; one species of
Cratomorphus--a long slender insect with yellow wing-cases marked with
two parallel black lines--is "the firefly" known to every one and
excessively abundant in the southern countries of La Plata. This insect
is strictly diurnal in its habits--as much so, in fact, as diurnal
butterflies. They are seen flying about, wooing their mates, and feeding
on composite and umbelliferous flowers at all hours of the day, and are
as active as wasps during the full glare of noon. Birds do not feed on
them, owing to the disagreeable odour, resembling that of phosphorus,
they emit, and probably because they are to be uneatable; but their
insect enemies are not so squeamish, and devour them readily, just as
they also do the blister-fly, which one would imagine a morsel fitted to
disagree with any stomach. One of their enemies is the Monedula wasp;
another, a fly, of the rapacious Asilidas family; and this fly is also a
wasp in appearance, having a purple body and bright red wings, like a
Pepris, and this mimetic resemblance doubtless serves it as a protection
against birds. A majority of raptorial insects are, however, nocturnal,
and from all these enemies that go about under cover of night, the
firefly, as Kirby and Spence rightly conjectured, protects itself, or
rather is involuntarily protected, by means of its frequent flashing
light. We are thus forced to the conclusion that, while the common house
fly and many other diurnal insects spend a considerable portion of the
daylight in purely sportive exercises, the firefly, possessing in its
light a protection from nocturnal enemies, puts off its pastimes until
the evening; then, when its carnival of two or three hours' duration is
over, retires also to rest, putting out its candle, and so exposing
itself to the dangers which surround other diurnal species during the
hours of darkness. I have spoken of the firefly's pastimes advisedly,
for I have really never been able to detect it doing anything in the
evening beyond flitting aimlessly about, like house flies in a room,
hovering and revolving in company by the hour, apparently for amusement.
Thus, the more closely we look at the facts, the more unsatisfactory
does the explanation seem. That the firefly should have become possessed
of so elaborate a machinery, producing incidentally such splendid
results, merely as a protection against one set of enemies for a portion
only of the period during which they are active, is altogether
incredible.
The current theory, which we owe to Belt, is a prettier one. Certain
insects (also certain Batrachians, reptiles, &c.) are unpalatable to the
rapacious kinds; it is therefore a direct advantage to these unpalatable
species to be distinguishable from all the persecuted, and the more
conspicuous and well-known they are, the less likely are they to be
mistaken by birds, insectivorous mammals, &c., for eatable kinds and
caught or injured. Hence we find that many such species have acquired
for their protection very brilliant or strongly-contrasted
colours--warning colours--which insect-eaters come to know.
The firefly, a soft-bodied, slow-flying insect, is easily caught and
injured, but it is not fit for food, and, therefore, says the theory,
lest it should be injured or killed by mistake, it has a fiery spark to
warn enemies---birds, bats, and rapacious insects--that it is uneatable.
The theory of warning colours is an excellent one, but it has been
pushed too far. We have seen that one of the most common fireflies is
diurnal in habits, or, at any rate, that it performs all the important
business of its life by day, when it has neither bright colour nor light
to warn its bird enemies; and out of every hundred species of
insect-eating birds at least ninety-nine are diurnal. Raptorial insects,
as I have said, feed freely on fireflies, so that the supposed warning
is not for them, and it would be hard to believe that the magnificent
display made by luminous insects is useful only in preventing accidental
injuries to them from a few crepuscular bats and goatsuckers. And to
believe even this we should first have to assume that bats and
goatsuckers are differently constituted from all other creatures; for in
other animals--insects, birds, and mammalians--the appearance of fire by
night seems to confuse and frighten, but it certainly cannot be said to
_warn,_ in the sense in which that word is used when we speak of the
brilliant colours of some butterflies, or even of the gestures of some
venomous snakes, and of the sounds they emit.
Thus we can see that, while the old theory of Kirby and Spence had some
facts to support it, the one now in vogue is purely fanciful. Until some
better suggestion is made, it would perhaps be as well to consider the
luminous organ as having "no very close and direct relation to present
habits of life." About their present habits, however, especially their
crepuscular habits, there is yet much to learn. One thing I have
observed in them has always seemed very strange to me. Occasionally an
individual insect is seen shining with a very large and steady light, or
with a light which very gradually decreases and increases in power, and
at such times it is less active than at others, remaining for long
intervals motionless on the leaves, or moving with a very slow flight.
In South America a firefly displaying this abnormal splendour is said to
be dying, and it is easy to imagine how such a notion originated. The
belief is, however, erroneous, for sometimes, on very rare occasions,
all the insects in one place are simultaneously affected in the same
way, and at such times they mass themselves together in myriads, as if
for migration, or for some other great purpose. Mr. Bigg-Wither, in
South Brazil, and D'Albertis, in New Guinea, noticed these firefly
gatherings; I also once had the rare good fortune to witness a
phenomenon of the kind on a very grand scale. Riding on the pampas one
dark evening an hour after sunset, and passing from high ground
overgrown with giant thistles to a low plain covered with long grass,
bordering a stream of water, I found it all ablaze with myriads of
fireflies. I noticed that all the insects gave out an exceptionally
large, brilliant light, which shone almost steadily. The long grass was
thickly studded with them, while they literally swarmed in the air, all
moving up the valley with a singularly slow and languid flight. When I
galloped down into this river of phosphorescent fire, my horse plunged
and snorted with alarm. I succeeded at length in quieting him, and then
rode slowly through, compelled to keep my mouth and eyes closed, so
thickly did the insects rain on to my face. The air was laden with the
sickening phosphorous smell they emit, but when I had once got free of
the broad fiery zone, stretching away on either hand for miles along the
moist valley, I stood still and gazed back for some time on a scene the
most wonderful and enchanting I have ever witnessed.
The fascinating and confusing effect which the appearance of fire at
night has on animals is a most interesting subject; and although it is
not probable that anything very fresh remains to be said about it, I am
tempted to add here the results of my own experience.
When travelling by night, I have frequently been struck with the
behaviour of my horse at the sight of natural fire, or appearance of
fire, always so different from that caused by the sight of fire
artificially created. The steady gleam from the open window or door of a
distant house, or even the unsteady wind-tossed flame of some lonely
camp-fire, has only served to rouse a fresh spirit in him and the desire
to reach it; whereas those infrequent displays of fire which nature
exhibits, such as lightning, or the ignis fatuus, or even a cloud of
fireflies, has always produced a disquieting effect. Experience has
evidently taught the domestic horse to distinguish a light kindled by
man from all others; and, knowing its character, he is just as well able
as his rider to go towards it without experiencing that confusion of
mind caused by a glare in the darkness, the origin and nature of which
is a mystery. The artificially-lighted fire is to the horse only the
possible goal of the journey, and is associated with the thought of rest
and food. Wild animals, as a rule, at any rate in thinly-settled
districts, do not know the meaning of any fire; it only excites
curiosity and fear in them; and they are most disturbed at the sight of
fires made by man, which are brighter and steadier than most natural
fires. We can understand this sensation in animals, since we ourselves
experience a similar one (although in a less degree and not associated
with fear) in the effect which mere brightness has on us, both by day
and night.
On riding across the monotonous grey Patagonian uplands, where often for
hours one sees not the faintest tinge of bright colour, the intense
glowing crimson of a cactus-fruit, or the broad shining white bosom of
the Patagonian eagle-buzzard (Buteo erythronotus), perched on the summit
of a distant bush, has had a strangely fascinating effect on me, so that
I have been unable to take my eyes off it as long as it continued before
me. Or in passing through extensive desolate marshes, the dazzling white
plumage of a stationary egret has exercised the same attraction. At
night we experience the sensation in a greater degree, when the silver
sheen of the moon makes a broad path on the water; or when a meteor
leaves a glowing track across the sky; while a still more familiar
instance is seen in the powerful attraction on the sight of glowing
embers in a darkened room. The mere brightness, or vividness of the
contrast, fascinates the mind; but the effect on man is comparatively
weak, owing to his fiery education and to his familiarity with brilliant
dyes artificially obtained from nature. How strong this attraction of
mere brightness, even where there is no mystery about it, is to wild
animals is shown by birds of prey almost invariably singling out white
or bright-plumaged birds for attack where bright and sober-coloured
kinds are mingled together. By night the attraction is immeasurably
greater than by day, and the light of a fire steadily gazed at quickly
confuses the mind. The fires which, travellers make for their protection
actually serve to attract the beasts of prey, but the confusion and fear
caused by the bright glare makes it safe for the traveller to lie down
and sleep in the light. Mammals do not lose their heads altogether,
because they are walking on firm ground where muscular exertion and an
exercise of judgment are necessary at every step; whereas birds floating
buoyantly and with little effort through the air are quickly bewildered.
Incredible numbers of migratory birds kill them-selves by dashing
against the windows of lighthouses; on bright moonlight nights the
voyagers are comparatively safe; but during dark cloudy weather the
slaughter is very great; over six hundred birds were killed by striking
a lighthouse in Central America in a single night. On insects the effect
is the same as on the higher animals: on the ground they are attracted
by the light, but keep, like wolves and tigers, at a safe distance from
it; when rushing through the air and unable to keep their eyes from it
they fly into it, or else revolve about it, until, coming too close,
their wings are singed.
I find that when I am on horseback, going at a swinging gallop, a bright
light affects me far more powerfully than when I am trudging along on
foot. A person mounted on a bicycle and speeding over a level plain on a
dark night, with nothing to guide him except the idea of the direction
in his mind, would be to some extent in the position of the migratory
bird. An exceptionally brilliant ignis fatuus flying before him would
affect him as the gleam of a lamp placed high above the surface affects
the migrants: he would not be able to keep his eyes from it, but would
quickly lose the sense of direction, and probably end his career much as
the bird does, by breaking his machine and perhaps his bones against
some unseen obstruction in the way.
CHAPTER XIV.
FACTS AND THOUGHTS ABOUT SPIDERS.
Some time ago, while turning over a quantity of rubbish in a little-used
room, I disturbed a large black spider. Rushing forth, just in time to
save itself from destruction through the capsizing of a pile of books,
it paused for one moment, took a swift comprehensive glance at the
position, then scuttled away across the floor, and was lost in an
obscure corner of the room. This incident served to remind me of a fact
I was nearly forgetting, that England is not a spiderless country. A
foreigner, however intelligent, coming from warmer regions, might very
easily make that mistake. In Buenos Ayres, the land of my nativity,
earth teems with these interesting little creatures. They abound in and
on the water, they swarm in the grass and herbage, which everywhere
glistens with the silvery veil they spin over it. Indeed it is scarcely
an exaggeration to say that there is an atmosphere of spiders, for they
are always floating about invisible in the air; their filmy threads are
unfelt when they fly against you; and often enough you are not even
aware of the little arrested aeronaut hurrying over your face with feet
lighter than the lightest thistledown.
It is somewhat strange that although, where other tribes of living
creatures are concerned, I am something of a naturalist, spiders I have
always observed and admired in a non-scientific spirit, and this must be
my excuse for mentioning the habits of some spiders without giving their
specific names--an omission always vexing to the severely-technical
naturalist. They have ministered to the love of the beautiful, the
grotesque, and the marvellous in me; but I have never _collected_ a
spider, and if I wished to preserve one should not know how to do it. I
have been "familiar with the face" of these monsters so long that I have
even learnt to love them; and I believe that if Emerson rightly predicts
that spiders are amongst the things to be expelled from earth by the
perfected man of the future, then a great charm and element of interest
will be lost to nature. Though loving them, I cannot, of course, feel
the same degree of affection towards all the members of so various a
family. The fairy gossamer, scarce seen, a creature of wind and
sunshine; the gem-like Epeira in the centre of its Starry web; even the
terrestrial Salticus, with its puma-like strategy, certainly appeal more
to our aesthetic feelings than does the slow heavy Mygale, looking at a
distance of twenty yards away, as he approaches you, like a gigantic
cockroach mounted on stilts. The rash fury with which the female
wolf-spider defends her young is very admirable; but the admiration she
excites is mingled with other feelings when we remember that the brave
mother proves to her consort a cruel and cannibal spouse.
Possibly my affection for spiders is due in a great measure to the
compassion I have always felt for them. Pity, 'tis said, is akin to
love; and who can help experiencing that tender emotion that considers
the heavy affliction nature has laid on the spiders in compensation for
the paltry drop of venom with which she, unasked, endowed them! And
here, of course, I am alluding to the wasps. These insects, with a
refinement of cruelty, prefer not to kill their victims outright, but
merely maim them, then house them in cells where the grubs can vivisect
them at leisure. This is one of those revolting facts the fastidious
soul cannot escape from in warm climates; for in and out of open windows
and doors, all day long, all the summer through, comes the busy
beautiful mason-wasp. A long body, wonderfully slim at the waist, bright
yellow legs and thorax, and a dark crimson abdomen,--what object can be
prettier to look at? But in her life this wasp is not beautiful. At
home in summer they were the pests of my life, for nothing would serve
to keep them out. One day, while we were seated at dinner, a clay nest,
which a wasp had succeeded in completing unobserved, detached itself
from the ceiling and fell with a crash on to the table, where it was
shattered to pieces, scattering a shower of green half-living spiders
round it. I shall never forget the feeling of intense repugnance I
experienced at the sight, coupled with detestation of the pretty but
cruel little architect. There is, amongst our wasps, even a more
accomplished spider-scourge than the mason-wasp, and I will here give a
brief account of its habits. On the grassy pampas, dry bare spots of
soil are resorted to by a class of spiders that either make or take
little holes in the ground to reside in, and from which they rush forth
to seize their prey. They also frequently sit inside their dens and
patiently wait there for the intrusion of some bungling insect. Now, in
summer, to a dry spot of ground like this, comes a small wasp, scarcely
longer than a blue-bottle fly, body and wings of a deep shining purplish
blue colour, with only a white mark like a collar on the thorax. It
flirts its blue wings, hurrying about here and there, and is extremely
active, and of a slender graceful figure--the type of an assassin. It
visits and explores every crack and hole in the ground, and, if you
watch it attentively, you will at length see it, on arriving at a hole,
give a little start backwards. It knows that a spider lies concealed
within. Presently, having apparently matured a plan of attack, it
disappears into the hole and remains there for some time. Then, just
when you are beginning to think that the little blue explorer has been
trapped, out it rushes, flying in terror, apparently, from the spider
who issues close behind in hot pursuit; but, before they are three
inches away from the hole, quick as lightning the wasp turns on its
follower, and the two become locked together in a deadly embrace.
Looking like one insect, they spin rapidly round for a few moments, then
up springs the wasp--victorious. The wretched victim is not dead; its
legs move a little, but its soft body is paralyzed, and lies collapsed,
flabby, and powerless as a stranded jellyfish. And this is the
invariable result of every such conflict. In other classes of beings,
even the weakest hunted thing occasionally succeeds in inflicting pain
on its persecutor, and the small trembling mouse, unable to save itself,
can sometimes make the cat shriek with paiu; but there is no weak spot
in the wasp's armour, no fatal error of judgment, not even an accident,
ever to save the wretched victim from its fate. And now comes the most
iniquitous part of the proceeding. When the wasp has sufficiently rested
after the struggle, it deliberately drags the disabled spider back into
its own hole, and, having packed it away at the extremity, lays an egg
alongside of it, then, coming out again, gathers dust and rubbish with
which it fills up and obliterates the hole; and, having thus concluded
its Machiavellian task, it flies cheerfully off in quest of another
victim.
The extensive Epeira family supply the mason-wasps and other
spider-killers with the majority of their victims. These spiders have
soft, plump, succulent bodies like pats of butter; they inhabit trees
and bushes chiefly, where their geometric webs-betray their whereabouts;
they are timid, comparatively innocuous, and reluctant to quit the
shelter of their green bower, made of a rolled-up leaf; so that there
are many reasons why they should be persecuted. They exhibit a great
variety of curious forms; many are also very richly coloured; but even
their brightest hues--orange, silver, scarlet--have not been given
without regard to the colouring of their surroundings. Green-leafed
bushes arc frequented by vividly green Epeiras, but the imitative
resemblance does not quite end here. The green spider's method of
escape, when the bush is roughly shaken, is to drop itself down on the
earth, where it lies simulating death. In falling, it drops just as a
green leaf would drop, that is, not quite so rapidly as a round, solid
body like a beetle or spider. Now in the bushes there is another Epeira,
in size and form like the last, but differing in colour; for instead of
a vivid green, it is of a faded yellowish white--the exact hue of a
dead, dried-up leaf. This spider, when it lets itself drop--for it has
the same protective habit as the other--falls not so rapidly as a green
freshly broken off leaf or as the green spider would fall, but with a
slower motion, precisely like a leaf withered up till it has become
almost light as a feather. It is not difficult to imagine how this comes
about: either a thicker line, or a greater stiffness or tenacity of the
viscid fluid composing the web and attached to the point the spider
drops from, causes one to fall slower than the other. But how many
tentative variations in the stiffness of the web material must there
have been before the precise degree was attained enabling the two
distinct species, differing in colour, to complete their resemblance to
falling leaves--a fresh green leaf in one case and a dead, withered leaf
in the other!
The Tetragnatha--a genus of the Epeira family, and known also in
England--are small spiders found on the margin of streams. Their bodies
are slender, oblong, and resembling a canoe in shape; and when they sit
lengthwise on a stem or blade of grass, their long, hair-like legs
arranged straight before and behind them, it is difficult to detect
them, so closely do they resemble a discoloured stripe on the herbage. A
species of Tetragnatha with a curious modification of structure abounds
on the pampas. The long leg of this spider is no thicker than a bristle
from a pig's back, but at the extremity it is flattened and broad,
giving it a striking resemblance to an oar. These spiders are only found
in herbage overhanging the borders of streams: they are very numerous,
and, having a pugnacious temper, are incessantly quarrelling; and it
frequently happens that in these encounters, or where they are pursuing
each other through the leaves, they drop into the water below. I
believe, in fact, that they often drop themselves purposely into it as
the readiest means of escape when hard pressed. When this happens, the
advantage of the modified structure of the legs is seen. The fallen
spider, sitting boat-like on the surface, throws out its long legs, and,
dipping the broad ends into the water, literally rows itself rapidly to
land.
The gossamer-spider, most spiritual of living things, of which there are
numerous species, some extremely beautiful in colouring and markings, is
the most numerous of our spiders. Only when the declining sun flings a
broad track of shiny silver light on the plain does one get some faint
conception of the unnumbered millions of these buoyant little creatures
busy weaving their gauzy veil over the earth and floating unseen, like
an ethereal vital dust, in the atmosphere.
This spider carries within its diminutive abdomen a secret which will
possibly serve to vex subtle intellects for a long time to come; for it
is hard to believe that merely by mechanical force, even aided by
currents of air, a creature half as big as a barley grain can
instantaneously snoot out filaments twenty or thirty inches long, and by
means of which it floats itself in the air.
Naturalists are now giving a great deal of attention to the migrations
of birds in different parts of the world: might not insect and spider
migrations be included with advantage to science in their observations?
The common notion is that the gossamer makes use of its unique method of
locomotion, only to shift its quarters, impelled by want of food or
unfavourable conditions--perhaps only by a roving disposition. I believe
that besides these incessant flittings about from place to place
throughout the summer the gossamer-spiders have great periodical
migrations which are, as a rule, in-visible, since a single floating web
cannot be remarked, and each individual rises and floats away by itself
from its own locality when influenced by the instinct. When great
numbers of spiders rise up simultaneously over a large area, then,
sometimes, the movement forces itself on our attention; for at such
times the whole sky may be filled with visible masses of floating web.
All the great movements of gossamers I have observed have occurred in
the autumn, or, at any rate, several weeks after the summer solstice;
and, like the migrations of birds at the same season of the year, have
been in a northerly direction. I do not assert or believe that the
migratory instinct in the gossamer is universal. In a moist island, like
England, for instance, where the condition of the atmosphere is seldom
favourable, and where the little voyagers would often be blown by
adverse winds to perish far out at sea, it is difficult to believe that
such migrations take place. But where they inhabit a vast area of land,
as in South America, extending without interruption from the equator to
the cold Magellanic regions, and where there is a long autumn of dry,
hot weather, then such an instinct as migration might have been
developed. For this is not a faculty merely of a few birds: the impulse
to migrate at certain seasons affects birds, insects, and even mammals.
In a few birds only is it highly developed, but the elementary feeling,
out of which the wonderful habit of the swallow has grown, exists widely
throughout animated nature. On the continent of Europe it also seems
probable that a great autumnal movement of these spiders takes place;
although, I must confess, I have no grounds for this statement, except
that the floating gossamer is called in Germany "Der fliegender
Summer"--the flying or departing summer.
I have stated that all migrations of gossamers I have witnessed have
been in the autumn; excepting in one instance, these flights occurred
when the weather was still hot and dry. The exceptionally late migration
was on March 22--a full month after the departure of martins,
humming-birds, flycatchers, and most other true bird-migrants. It struck
me as being so remarkable, and seems to lend so much force to the idea I
have suggested, that I wish to give here an exact copy of the entries
made at the time and on the spot in my notebook.
"March 22. This afternoon, while I was out shooting, the
gossamer-spiders presented an appearance quite new to me. Walking along
a stream (the Conchitas, near Buenos Ayres), I noticed a broad white
line skirting the low wet ground. This I found was caused by gossamer
web lying in such quantities over the earth as almost to hide the grass
ad thistles under it. The white zone was about twenty yards wide, and
outside it only a few scattered webs were visible on the grass; its
exact length I did not ascertain, but followed it for about two miles
without finding the end. The spiders were so numerous that they
continually baulked one another in their efforts to rise in the air. As
soon as one threw out its lines they would become entangled with those
of another spider, lanced out at the same moment; both spiders would
immediately seem to know the cause of the trouble, for as soon as their
lines fouled they would rush angrily towards each other, each trying to
drive the other from the elevation. Notwithstanding these difficulties,
numbers were continually floating off on the breeze which blew from the
south.
"I noticed three distinct species: one with a round scarlet body;
another, velvet black, with large square cephalothorax and small pointed
abdomen; the third and most abundant kind were of different shades of
olive green, and varied greatly in size, the largest being fully a
quarter of an inch in length. Apparently these spiders had been driven
up from the low ground along the stream where it was wet, and had
congregated along the borders of the dry ground in readiness to migrate.
"25th. Went again to visit the spiders, scarcely expecting to find them,
as, since first seeing them, we have had much wind and rain. To my
surprise I found them in greatly increased numbers: on the tops of
cardoons, posts, and other elevated situations they were literally lying
together in heaps. Most of them were large and of the olive-coloured
species; their size had probably prevented them from getting away
earlier, but they were now floating off in great numbers, the weather
being calm and tolerably dry. To-day I noticed a new species with a grey
body, elegantly striped with black, and pink legs--a very pretty spider.
"26th. Went again to-day and found that the whole vast army of
gossamers, with the exception of a few stragglers sitting on posts and
dry stalks, had vanished. They had taken advantage of the short spell of
fine weather we are now having, after an unusually wet and boisterous
autumn, to make their escape."
Here it seemed to me that a conjunction of circumstances--first, the
unfavourable season preventing migration at the proper time, and
secondly, the strip of valley out of which the spiders had been driven
to the higher ground till they were massed together--only served to make
visible and evident that a vast annual migration takes place which we
have only to look closely for to discover.
One of the most original spiders in Buenos Ayres--mentally original, I
mean--is a species of Pholcus; a quiet, inoffensive creature found in
houses, and so abundant that they literally swarm where they are not
frequently swept away from ceilings and obscure corners. Certainly it
seems a poor spider after the dynamical and migratory gossamer; but it
happens, curiously enough, that a study of the habits of this dusty
domestic creature leads us incidentally into the realms of fable and
romance. It is remarkable for the extreme length of its legs, and
resembles in colour and general appearance a crane fly, but is double
the size of that insect. It has a singular method of protecting itself:
when attacked or approached even, gathering its feet together and
fastening them to the centre of its web, it swings itself round and
round with the velocity of a whirligig, so that it appears like a mist
on the web, offering no point for an enemy to strike at. "When a fly is
captured the spider approaches it cautiously and spins a web round it,
continually narrowing the circle it describes, until the victim is
inclosed in a cocoon-like covering. This is a common method with
spiders; but the intelligence--for I can call it by no other word--of
the Pholcus has supplemented this instinctive procedure with a very
curious and unique habit. The Pholcus, in spite of its size, is a weak
creature, possessing little venom to despatch its prey with, so that it
makes a long and laborious task of killing a fly. A fly when caught in
a web is a noisy creature, and it thus happens that when the
Daddylonglegs--as Anglo-Argentines have dubbed this species--succeeds in
snaring a captive the shrill outrageous cries of the victim are heard
for a long time--often for ten or twelve minutes. This noise greatly
excites other spiders in the vicinity, and presently they are seen
quitting their webs and flurrying to the scene of conflict. Sometimes
the captor is driven off, and then the strongest or most daring spider
carries away the fly. But where a large colony are allowed to continue
for a long time in undisturbed possession of a ceiling, when one has
caught a fly he proceeds rapidly to throw a covering of web over it,
then, cutting it away, drops it down and lets it hang suspended by a
line at a distance of two or three feet from the ceiling. The other
spiders arrive on the scene, and after a short investigation retreat to
their own webs, and when the coast is clear our spider proceeds to draw
up the captive fly, which is by this time exhausted with its struggles."
Now, I have repeatedly remarked that all spiders, when the shrill
humming of an insect caught in a web is heard near them, become
agitated, like the Pholcus, and will, in the same way, quit their own
webs and hurry to the point the sound proceeds from. This fact convinced
me many years ago that spiders are attracted by the sound of musical
instruments, such as violins, concertinas, guitars, &c., simply because
the sound produces the same effect on them as the shrill buzzing of a
captive fly. I have frequently seen spiders come down walls or from
ceilings, attracted by the sound of a guitar, softly played; and by
gently touching metal strings, stretched on a piece of wood, I have
succeeded in attracting spiders on to the strings, within two or three
inches of my fingers; and I always noticed that the spiders seemed to be
eagerly searching for something which they evidently expected to find
there, moving about in an excited manner and looking very hungry and
fierce. I have no doubt that Pelisson's historical spider in the
Bastille came down in a mood and with a manner just as ferocious when
the prisoner called it with musical sounds to be fed.
The spiders I have spoken of up till now are timid, inoffensive
creatures, chiefly of the Epeira family; but there are many others
exceedingly high-spirited and, like some of the most touchy
hymenopteras, always prepared to "greatly quarrel" over matters of
little moment. The Mygales, of which we have several species, are not to
be treated with contempt. One is extremely abundant on the pampas, the
Mygale fusca, a veritable monster, covered with dark brown hair, and
called in the vernacular _aranea peluda_--hairy spider. In the hot
month of December these spiders take to roaming about on the open plain,
and are then everywhere seen travelling in a straight line with a slow
even pace. They are very great in attitudes, and when one is approached
it immediately throws itself back, like a pugilist preparing for an
encounter, and stands up so erect on its four hind feet that the under
surface of its body is displayed. Humble-bees are commonly supposed to
carry the palm in attitudinizing; and it is wonderful to see the
grotesque motions of these irascible insects when their nest is
approached, elevating their abdomens and two or three legs at a time, so
that they resemble a troupe of acrobats balancing themselves on their
heads or hands, and kicking their legs about in the air. And to impress
the intruder with the dangerous significance of this display they hum a
shrill warning or challenge, and stab at the air with their naked
stings, from which limpid drops of venom are seen to exude. These
threatening gestures probably have an effect. In the case of the hairy
spider, I do not think any creature, however stupid, could mistake its
meaning when it stands suddenly up, a figure horribly grotesque; then,
dropping down on all eights, charges violently forwards. Their long,
shiny black, sickle-shaped falces are dangerous weapons. I knew a native
woman who had been bitten on the leg, and who, after fourteen years,
still suffered at intervals acute pains in the limb.
The king of the spiders on the pampas is, however, not a Mygale, but a
Lycosa of extraordinary size, light grey in colour, with a black ring
round its middle. It is active and swift, and irritable to such a degree
that one can scarcely help thinking that in this species nature has
overshot her mark.
When a person passes near one--say, within three or four yards of its
lurking-place--it starts up and gives chase, and will often follow for a
distance of thirty or forty yards. I came once very nearly being bitten
by one of these savage creatures Riding at an easy trot over the dry
grass, I suddenly observed a spider pursuing me, leaping swiftly along
and keeping up with my beast. I aimed a blow with my whip, and the point
of the lash struck the ground close to it, when it instantly leaped upon
and ran up the lash, and was actually within three or four inches of my
hand when I flung the whip from me.
The gauchos have a very quaint ballad which tells that the city of
Cordova was once invaded by an army of monstrous spiders, and that the
townspeople went out with beating drums and flags flying to repel the
invasion, and that after firing several volleys they were forced to turn
and fly for their lives. I have no doubt that a sudden great increase of
the man-chasing spiders, in a year exceptionally favourable to them,
suggested this fable to some rhyming satirist of the town.
In conclusion of this part of my subject, I will describe a single
combat of a very terrible nature I once witnessed between two little
spiders belong-ing to the same species. One had a small web against a
wall, and of this web the other coveted possession. After vainly trying
by a series of strategic movements to drive out the lawful owner, it
rushed on to the web, and the two envenomed httle duellists closed in
mortal combat. They did nothing so vulgar and natural as to make use of
their falces, and never once actually touched each other, but the fight
was none the less deadly. Rapidly revolving about, or leaping over, or
passing under, each other, each endeavoured to impede or entangle his
adversary, and the dexterity with which each avoided the cunningly
thrown snare, trying at the same time to entangle its opponent, was
wonderful to see. At length, after this equal battle had raged for some
time, one of the combatants made some fatal mistake, and for a moment
there occurred a break in his motions; instantly the other perceived his
advantage, and began leaping backwards and forwards across his
struggling adversary with such rapidity as to confuse the sight,
producing the appearance of two spiders attacking a third one lying
between them. He then changed his tactics, and began revolving round and
round his prisoner, and very soon the poor vanquished wretch--the
aggressor, let us hope, in the interests of justice--was closely wrapped
in a silvery cocoon, which, unlike the cocoon the caterpillar weaves for
itself, was also its winding-sheet.
In the foregoing pages I have thrown together some of the most salient
facts I have noted; but the spider-world still remains to me a
wonderland of which I know comparatively nothing. Nor is any very
intimate knowledge of spiders to be got from books, though numberless
lists of new species are constantly being printed; for they have not yet
had, like the social bees and ants, many loving and patient chroniclers
of their ways. The Hubens and Lubbocks have been many; the Moggridges
few. But even a very slight study of these most versatile and
accomplished of nature's children gives rise to some interesting
reflections. One fact that strikes the mind very forcibly is the
world-wide distribution of groups of species possessing highly developed
instincts. One is the zebra-striped Salticus, with its unique
strategy--that is to say, unique amongst spiders. It is said that the
Australian savage approaches a kangaroo in the open by getting up in
sight of its prey and standing perfectly motionless till he is regarded
as an inanimate object, and every time the animal's attention wanders
advancing a step or two until sufficiently near to hurl his spear. The
Salticus approaches a fly in the same manner, till near enough to make
its spring. Another is the Trapdoor spider. Another the Dolomedes, that
runs over the surface of the water in pursuit of its prey, and dives
down to escape from its enemies; and, strangest of all, the Argyroneta,
that has its luminous dwelling at the bottom of streams; and just as a
mason carries bricks and mortar to its building, so does this spider
carry down bubbles of air from the surface to enlarge its mysterious
house, in which it lays its eggs and rears its young. Community of
descent must be supposed of species having such curious and complex
instincts; but how came these feeble creatures, unable to transport
themselves over seas and continents like the aerial gossamer, to be so
widely distributed, and inhabiting regions with such different
conditions? This can only be attributed to the enormous antiquity of the
species, and of this antiquity the earliness in which the instinct
manifests itself in the young spiders is taken as evidence.
A more important matter, the intelligence of spiders, has not yet
received the attention it deserves. The question of insect
intelligence--naturalists are agreed that insects do possess
intelligence--is an extremely difficult one; probably some of our
conclusions on this matter will have to be reconsidered. For instance,
we regard the Order Hymenoptera as the most intelligent because most of
the social insects are included in it; but it has not yet been proved,
probably never will be proved, that the social instincts resulted from
intelligence which has "lapsed." Whether ants and bees were more
intelligent than other insects during the early stages of their organic
societies or not, it will hardly be disputed by any naturalist who has
observed insects for long that many solitary species display more
intelligence in their actions than those that live in communities.
The nature of the spider's food and the difficulties in the way of
providing for their wants impose on them a life of solitude: hunger,
perpetual watchfulness, and the sense of danger have given them a
character of mixed ferocity and timidity. But these very conditions,
which have made it impossible for them to form societies like some
insects and progress to a state of things resembling civilization in
men, have served to develop the mind that is in a spider, making of him
a very clever barbarian-The spider's only weapon of defence---his
falces--are as poor a protection against the assaults of his insect foes
as are teeth and finger-nails in man employed against wolves, bears, and
tigers. And the spider is here even worse off than man, since his
enemies are winged and able to sweep down instantly on him from above;
they are also protected with an invulnerable shield, and are armedwith
deadly stings. Like man, also, the spider has a soft, unprotected body,
while his muscular strength, compared with that of the insects he has to
contend with, is almost _nil._ His position in nature then, with
relation to his enemies, is like that of man; only the spider has this
disadvantage, that he cannot combine with others for protection. That he
does protect himself and maintains his place in nature is due, not to
special instincts, which are utterly insufficient, but to the
intelligence which supplements them. At the same time this superior
cunning is closely related with, and probably results indirectly from,
the web he is provided with, and which is almost of the nature of an
artificial aid. Let us take the imaginary case of a man-like monkey, or
of an arboreal man, born with a cord of great length attached to his
waist, which could be either dragged after him or carried in a coil.
After many accidents, experience would eventually teach him to put it to
some use; practice would make him more and more skilful in handling it,
and, indirectly, it would be the means of developing his latent mental
faculties. He would begin by using it, as the monkey does its prehensile
tail, to swing himself from branch to branch, and finally, to escape
from an enemy or in pursuit of his prey, he would be able by means of
his cord to drop himself with safety from the tallest trees, or fly down
the steepest precipices. He would coil up his cord to make a bed to lie
on, and also use it for binding branches together when building himself
a refuge. In a close fight, he would endeavour to entangle an adversary,
and at last he would learn to make a snare with it to capture his prey.
To all these, and to a hundred other uses, the spider has put his web.
And when we see him spread his beautiful geometric snare, held by lines
fixed to widely separated points, while he sits concealed in his
web-lined retreat amongst the leaves where every touch on the
far-reaching structure is telegraphed to him by the communicating line
faithfully as if a nerve had been touched, we must admire the wonderful
perfection to which he has attained in the use of his cord. By these
means he is able to conquer creatures too swift and strong for him, and
make them his prey. When we see him repairing damages, weighting his
light fabric in windy weather with pebbles or sticks, as a fisher
weights his net, and cutting loose a captive whose great strength
threatens the destruction of the web, then we begin to suspect that he
has, above his special instinct, a reason that guides, modifies, and in
many ways supplements it. It is not, however, only on these great
occasions, when the end is sought by unusual means, that spiders show
their intelligence; for even these things might be considered by some as
merely parts of one great complex instinct; but at all times, in all
things, the observer who watches them closely cannot fail to be
convinced that they possess a guiding principle which is not mere
instinct. What the stick or stone was to primitive man, when he had made
the discovery that by holding it in his hand he greatly increased the
force of his blow, the possession of a web has been to the spider in
developing that spark of intellect which it possesses in common with all
animal organisms.
CHAPTER XV.
THE DEATH-FEIGNING INSTINCT.
Most people are familiar with the phenomenon of "death-feigning,"
commonly seen in coleopterous insects, and in many spiders. This highly
curious instinct is also possessed by some vertebrates. In insects it is
probably due to temporary paralysis occasioned by sudden concussion, for
when beetles alight abruptly, though voluntarily, they assume that
appearance of death, which lasts for a few moments. Some species,
indeed, are so highly sensitive that the slightest touch, or even a
sudden menace, will instantly throw them into this motionless,
death-simulating condition. Curiously enough, the same causes which
produce this trance in slow-moving species, like those of Scarabseus for
example, have a precisely contrary effect on species endowed with great
activity. Rapacious beetles, when disturbed, scuttle quickly out of
sight, and some water-beetles spin about the surface, in circles or
zigzag lines, so rapidly as to confuse the eye. Our common long-legged
spiders (Pholcus) when approached draw their feet together in the middle
of the web, and spin the body round with such velocity as to resemble a
whirligig.
Certain mammals and birds also possess the death-simulating instinct,
though it is hardly possible to believe that the action springs from the
same immediate cause in vertebrates and in insects. In the latter it
appears to be a purely physical instinct, the direct result of an
extraneous cause, and resembling the motions of a plant. In mammals and
birds it is evident that violent emotion, and not the rough handling
experienced, is the final cause of the swoon.
Passing over venomous snakes, skunks, and a few other species in which
the presence of danger excites only anger, fear has a powerful, and in
some cases a disabling, effect on animals; and it is this paralyzing
effect of fear on which the death-feigning instinct, found only in a few
widely-separated species, has probably been built up by the slow
cumulative process of natural selection.
I have met with some curious instances of the paralyzing effect of fear.
I was told by some hunters in an outlying district of the pampas of its
effect on a jaguar they started, and which took refuge in a dense clump
of dry reeds. Though they could see it, it was impossible to throw the
lasso over its head, and, after vainly trying to dislodge it, they at
length set fire to the reeds. Still it refused to stir, but lay with
head erect, fiercely glaring at them through the flames. Finally it
disappeared from sight in the black smoke; and when the fire had burnt
itself out, it was found, dead and charred, in the same spot.
On the pampas the gauchos frequently take the black-necked swan by
frightening it. When the birds are feeding or resting on the grass, two
or three men or boys on horseback go quietly to leeward of the flock,
and when opposite to it suddenly wheel and charge it at full speed,
uttering loud shouts, by which the birds are thrown into such terror
that they are incapable of flying, and are quickly despatched.
I have also seen gaucho boys catch the Silver-bill (Lichenops
perspicillata) by hurling a stick or stone at the bird, then rushing at
it, when it sits perfectly still, disabled by fear, and allows itself to
be taken. I myself once succeeded in taking a small bird of another
species in the same way.
Amongst mammals our common fox (Canis azarae), and one of the opossums
(Didelphys azarae), are strangely subject to the death-simulating swoon.
For it does indeed seem strange that animals so powerful, fierce, and
able to inflict such terrible injury with their teeth should also
possess this safeguard, apparently more suited to weak inactive
creatures that cannot resist or escape from an enemy and to animals very
low down in the scale of being. When a fox is caught in a trap or run
down by dogs he fights savagely at first, but by-and-by relaxes his
efforts, drops on the ground, and apparently yields up the ghost. The
deception is so well carried out, that dogs are constantly taken in by
it, and no one, not previously acquainted with this clever trickery of
nature, but would at once pronounce the creature dead, and worthy of
some praise for having perished in so brave a spirit. Now, when in this
condition of feigning death, I am quite sure that the animal does not
altogether lose consciousness. It is exceedingly difficult to discover
any evidence of life in the opossum; but when one withdraws a little way
from the feigning fox, and watches him very attentively, a slight
opening of the eye may be detected; and, finally, when left to himself,
he does not recover and start up like an animal that has been stunned,
but slowly and cautiously raises his head first, and only gets up when
his foes are at a safe distance. Yet I have seen gauchos, who are very
cruel to animals, practise the most barbarous experiments on a captive
fox without being able to rouse it into exhibiting any sign of life.
This has greatly puzzled me, since, if death-feigning is simply a
cunning habit, the animal could not suffer itself to be mutilated
without wincing. I can only believe that the fox, though not insensible,
as its behaviour on being left to itself appears to prove, yet has its
body thrown by extreme terror into that benumbed condition which
simulates death, and during which it is unable to feel the tortures
practised on it.
The swoon sometimes actually takes place before the animal has been
touched, and even when the exciting cause is at a considerable distance.
I was once riding with a gaucho, when we saw, on the open level ground
before us, a fox, not yet fully grown, standing still and watching our
approach. All at once it dropped, and when we came up to the spot it was
lying stretched out, with eyes closed, and apparently dead. Before
passing on my companion, who said it was not the first time he had seen
such a thing, lashed it vigorously with his whip for some moments, but
without producing the slightest effect.
The death-feigning instinct is possessed in a very marked degree by the
spotted tinamou or common partridge of the pampas (Nothura maculosa).
When captured, after a few violent struggles to escape, it drops its
head, gasps two or three times, and to all appearances dies. If, when
you have seen this, you release your hold, the eyes open instantly, and,
with startling suddenness and a noise of wings, it is up and away, and
beyond your reach for ever. Possibly, while your grasp is on the bird it
does actually become insensible, though its recovery from that condition
is almost instantaneous. Birds when captured do sometimes die in the
hand, purely from terror. The tinamou is excessively timid, and
sometimes when birds of this species are chased--for gaucho boys
frequently run them down on horseback--and when they find no burrows or
thickets to escape into, they actually drop down dead on the plain.
Probably, when they feign death in their captor's hand, they are in
reality very near to death.
CHAPTER XVI.
HUMMING-BIRDS.
Humming-birds are perhaps the very loveliest things in nature, and many
celebrated writers have exhausted their descriptive powers in vain
efforts to picture them to the imagination. The temptation was certainly
great, after describing the rich setting of tropical foliage and flower,
to speak at length of the wonderful gem contained within it; but they
would in this case have been wise to imitate that modest novel-writer
who introduced a blank space on the page where the description of his
matchless heroine should have appeared. After all that has been written,
the first sight of a living humming-bird, so unlike in its beauty all
other beautiful things, comes like a revelation to the mind. To give any
true conception of it by means of mere word-painting is not more
impossible than it would be to bottle up a supply of the "living
sunbeams" themselves, and convey them across the Atlantic to scatter
them in a sparkling shower over the face of England.
Doubtless many who have never seen them in a state of nature imagine
that a tolerably correct idea of their appearance can be gained from
Gould's colossal monograph. The pictures there, however, only represent
dead humming-birds. A dead robin is, for purposes of bird-portraiture,
as good as a live robin; the same may be said of even many
brilliant-plumaged species less aerial in their habits than
humming-birds. In butterflies the whole beauty is seldom seen until the
insect is dead, or, at any rate, captive. It was not when Wallace saw
the Ornithoptera croesus flying about, but only when he held it in his
hands, and opened its glorious wings, that the sight of its beauty
overcame him so powerfully. The special kind of beauty which makes the
first sight of a humming-bird a revelation depends on the swift singular
motions as much as on the intense gem-like and metallic brilliancy of
the plumage.
The minute exquisite form, when the bird hovers on misty wings, probing
the flowers with its coral spear, the fan-like tail expanded, and
poising motionless, exhibits the feathers shot with many hues; and the
next moment vanishes, or all but vanishes, then reappears at another
flower only to vanish again, and so on successively, showing its
splendours not continuously, but like the intermitted flashes of the
firefly--this forms a picture of airy grace and loveliness that baffles
description. All this glory disappears when the bird is dead, and even
when it alights to rest on a bough. Sitting still, it looks like an
exceedingly attenuated kingfisher, without the pretty plumage of that
bird, but retaining its stiff artificial manner. No artist has been so
bold as to attempt to depict the bird as it actually appears, when
balanced before a flower the swift motion of the wings obliterates their
form, making them seem like a mist encircling the body; yet it is
precisely this formless cloud on which the glittering body hangs
suspended, which contributes most to give the humming-bird its wonderful
sprite-like or extra-natural appearance. How strange, then, to find
bird-painters persisting in their efforts to show the humming-bird
flying! When they draw it stiff and upright on its perch the picture is
honest, if ugly; the more ambitious representation is a delusion and a
mockery.
Coming to the actual colouring--the changeful tints that glow with such
intensity on the scale-like feathers, it is curious to find that Gould
seems to have thought that all difficulties here had been successfully
overcome. The "new process" he spoke so confidently about might no doubt
be used with advantage in reproducing the coarser metallic reflections
on a black plumage, such as we see in the corvine birds; but the
glittering garment of the humming-bird, like the silvery lace woven by
the Epeira, gemmed with dew and touched with rainbow-coloured light, has
never been and never can be imitated by art.
On this subject one of the latest observers of humming-birds, Mr.
Everard im Thurn, in his work on British Guiana, has the following
passage:--"Hardly more than one point of colour is in reality ever
visible in any one humming-bird at one and the same time, for each point
only shows its peculiar and glittering colour when the light falls upon
it from a particular direction. A true representation of one of these
birds would show it in somewhat sombre colours, except just at the one
point which, when the bird is in the position chosen for representation,
meets the light at the requisite angle, and that point alone should be
shown in full brilliance of colour. A flowery shrub is sometimes seen
surrounded by a cloud of humming-birds, all of one species, and each, of
course, in a different position. If someone would draw such a scene as
that, showing a different detail of colour in each bird, according to
its position, then some idea of the actual appearance of the bird might
be given to one who had never seen an example."
It is hardly to be expected that anyone will carry out the above
suggestion, and produce a monograph with pages ten or fifteen feet wide
by eighteen feet long, each one showing a cloud of humming-birds of one
species flitting about a flowery bush; but even in such a picture as
that would be, the birds, suspended on unlovely angular projections
instead of "hazy semicircles of indistinctness," and each with an
immovable fleck of brightness on the otherwise sombre plumage, would be
as unlike living humming-birds as anything in the older monographs.
Whether the glittering iridescent tints and singular ornaments for which
this family is famous result from the cumulative process of conscious or
voluntary sexual selection, as Darwin thought, or are merely the outcome
of a superabundant vitality, as Dr. A. R.. Wallace so strongly
maintains, is a question which science has not yet answered
satisfactorily. The tendency to or habit of varying in the direction of
rich colouring and beautiful or fantastic ornament, might, for all we
know to the contrary, have descended to humming-birds from some
diminutive, curiously-shaped, bright-tinted, flying reptile of arboreal
habits that lived in some far-off epoch in the world's history. It is
not, at all events, maintained by anyone that _all_ birds sprang
originally from one reptilian stock; and the true position of
humming-birds in a natural classification has not yet been settled, for
no intermediate forms exist connecting them with any other group, To the
ordinary mind they appear utterly unlike all other feathered creatures,
and as much entitled to stand apart as, for instance, the pigeon and
ostrich families. It has been maintained by some writers that they are
anatomically related to the swifts, although the differences separating
the two families appear so great as almost to stagger belief in this
notion. Now, however, the very latest authority on this subject, Dr.
Schufeldt, has come to the conclusion that swifts are only greatly
modified Passeres, and that the humming-birds should form an order by
themselves.
Leaving this question, and regarding them simply with the ornithological
eye that does not see far below the surface of things, when we have
sufficiently admired the unique beauty and marvellous velocity of
humming-birds, there is little more to be said about them. They are
lovely to the eye--indescribably so; and it is not strange that Gould
wrote rapturously of the time when he was at length "permitted to revel
in the delight of seeing the humming-bird in a state of nature." The
feeling, he wrote, which animated him with regard to these most
wonderful works of creation it was impossible to describe, and could
only be appreciated by those who have made natural history a study, and
who "pursue the investigations of her charming mysteries with ardour and
delight." This we can understand; but to what an astonishing degree the
feeling was carried in him, when, after remarking that enthusiasm and
excitement with regard to most things in life become lessened and
eventually deadened by time in most of us, he was able to add, "not
so, however, I believe, with those who take up the study of the Family
of Humming-birds!" It can only be supposed that he regarded natural
history principally as a "science of dead animals--a _necrology_," and
collected humming-birds just as others collect Roman coins, birds' eggs,
old weapons, or blue china, their zeal in the pursuit and faith in its
importance increasing with the growth of their treasures, until they at
last come to believe that though all the enthusiasms and excitements
which give a zest to the lives of other men fade and perish with time,
it is not so with their particular pursuit. The more rational kind of
pleasure experienced by the ornithologist in studying habits and
disposition no doubt results in a great measure from the fact that the
actions of the feathered people have a savour of intelligence in them.
Whatever his theory or conviction about the origin of instincts may
happen to be, or even if he has no convictions on the subject, it must
nevertheless seem plain to him that intelligence is, after all, in most
cases, the guiding principle of life, supplementing and modifying habits
to bring them into closer harmony with the environment, and enlivening
every day with countless little acts which result from judgment and
experience, and form no part of the inherited complex instincts. The
longer he observes any one species or individual, the more does he find
in it to reward his attention; this is not the case, however, with
humming-birds, which possess the avian body but do not rank mentally
with birds. The pleasure one takes in their beauty soon evaporates, and
is succeeded by no fresh interest, so monotonous and mechanical are all
their actions; and we accordingly find that those who are most familiar
with them from personal observation have very little to say about them.
A score of hummingbirds, of as many distinct species, are less to the
student of habits than one little brown-plurnaged bird haunting his
garden or the rush-bed of a neighbouring stream; and, doubtless, for a
reason similar to that which makes a lovely human face uninformed by
intellect seem less permanently attractive than many a homelier
countenance. He grows tired of seeing the feathered fairies perpetually
weaving their aerial ballet-dance about the flowers, and finds it a
relief to watch the little finch or wren or flycatcher of shy temper and
obscure protective colouring. Perhaps it possesses a graceful form and
melodious voice to give it aesthetic value, but even without such
accessories he can observe it day by day with increasing interest and
pleasure; and it only adds piquancy to the feeling to know that the
little bird also watches him with a certain amount of intelligent
curiosity and a great deal of suspicion, and that it studiously
endeavours to conceal from him all the little secrets its life which he
is bent on discovering.
It has frequently been remarked that humming birds are more like insects
than birds in disposition. Some species, on quitting their perch,
perform wide bee-like circles about the tree before shooting away in a
straight line. Their aimless attacks on other species approaching or
passing near them, even on large birds like hawks and pigeons, is a
habit they have in common with many solitary wood-boring bees. They
also, like dragon-flies and other insects, attack each other when they
come together while feeding; and in this case their action strangely
resembles that of a couple of butterflies, as they revolve about each
other and rise vertically to a great height in the air. Again, like
insects, they are undisturbed at the presence of man while feeding, or
even when engaged in building and incubation; and like various solitary
bees, wasps, &c., they frequently come close to a person walking or
standing, to hover suspended in the air within a few inches of his face;
and if then struck at they often, insect-like, return to circle round
his head. All other birds, even those which display the least
versatility, and in districts where man is seldom seen, show as much
caution as curiosity in his presence; they recognize in the upright
unfamiliar form a living being and a possible enemy. Mr. Whiteley, who
observed humming-birds in Peru, says it is an amusing sight to watch the
Lesbia nuna attempting to pass to a distant spot in a straight line
during a high wind, which, acting on the long tail feathers, carries it
quite away from the point aimed at. Insects presenting a large surface
to the wind are always blown from their course in the same way, for even
in the most windy districts they never appear to learn to guide
themselves; and I have often seen a butterfly endeavouring to reach an
isolated flower blown from it a dozen times before it finally succeeded
or gave up the contest. Birds when shaping their course, unless young
and inexperienced, always make allowance for the force of the wind.
Humming-birds often fly into open rooms, impelled apparently by a
fearless curiosity, and may then be chased about until they drop
exhausted or are beaten down and caught, and, as Gould says, "if then
taken into the hand, they almost immediately feed on any sweet, or pump
up any liquid that may be offered to them, without betraying either fear
or resentment at the previous treatment." Wasps and bees taken in the
same way endeavour to sting their captor, as most people know from
experience, nor do they cease struggling violently to free themselves;
but the dragon-fly is like the humming-bird, and is no sooner caught
after much ill-treatment, than it will greedily devour as many flies and
mosquitoes as one likes to offer it. Only in beings very low in the
scale of nature do we see the instinct of self-preservation in this
extremely simple condition, unmixed with reason or feeling, and so
transient in its effects. The same insensibility to danger is seen when
humming-birds are captured and confined in a room, and when, before a
day is over, they will flutter about their captor's face and even take
nectar from his lips.
Some observers have thought that hummingbirds come nearest to
humble-bees in their actions. I do not think so. Mr. Bates writes: "They
do not proceed in that methodical manner which bees follow, taking the
flowers seriatim, but skip about from one part of a tree to another in
the most capricious manner." I have observed humble-bees a great deal,
and feel convinced that they arc among the most highly intelligent of
the social hymenoptera. Humming-birds, to my mind, have a much closer
resemblance to the solitary wood-boring bees and to dragon-flies. It
must also be borne in mind that insects have very little time in which
to acquire experience, and that a large portion of their life, in the
imago state, is taken up with the complex business of reproduction.
The Trochilidae, although confined to one continent, promise to exceed
all other families--even the cosmopolitan finches and warblers--in
number of species. At present over five hundred are known, or as many as
all the species of birds in Europe together; and good reasons exist for
believing that very many more--not less perhaps than one or two hundred
species--yet remain to be discovered. The most prolific region, and
where humming-birds are most highly developed, is known to be West
Brazil and the eastern slopes of the Bolivian and Peruvian Andes. This
is precisely the least known portion of South America; the few
naturalists and collectors who have reached it have returned laden with
spoil, to tell us of a region surpassing all others in the
superabundance and beauty of its bird life. Nothing, however, which can
be said concerning these vast unexplored areas of tropical mountain and
forest so forcibly impresses us with the idea of the unknown riches
contained in them as the story of the Loddigesia mirabilis. This is
perhaps the most wonderful humming-bird known, and no one who had not
previously seen it figured could possibly form an idea of what it is
like from a mere description. An outline sketch of it would probably be
taken by most people as a fantastic design representing a bird-form in
combination with leaves, in size and shape resembling poplar leaves, but
on leaf-stalks of an impossible length, curving and crossing each other
so as to form geometrical figures unlike anything in nature. Yet this
bird (a single specimen) was obtained in Peru half a century ago, and
for upwards of twenty years after its discovery Gould tried to obtain
others, offering as much as fifty pounds for one; but no second specimen
ever gladdened his eyes, nor was anything more heard of it until
Stolzmann refound it in the year 1880.
The addition of many new species to the long list would, however, be a
matter of small interest, unless fresh facts concerning their habits and
structure were at the same time brought to light; but we can scarcely
expect that the as yet unknown species will supply any link connecting
the Trochilidae with other existing families of birds. The eventual
conclusion will perhaps be that this family has come down independently
from an exceedingly remote past, and with scarcely any modification.
While within certain very narrow limits humming-birds vary more than
other families, outside of these limits they appear relatively
stationary; and, conversely, other birds exhibit least variability in
the one direction in which humming-birds vary excessively. On account of
a trivial difference in habit they have sometimes been separated in two
sub-families: the Phaethornithinae, found in shady tropical forests; and
the Trochilinae, comprising humming-birds which inhabit open sunny
places--and to this division they mostly belong. In both of these purely
arbitrary groups, however, the aerial habits and manner of feeding
poised in the air are identical, although the birds living in shady
forests, where flowers are scarce, obtain their food principally from
the under surfaces of leaves. In their procreant habits the uniformity
is also very great. In all cases the nest is small, deep, cup-shaped, or
conical, composed of soft felted materials, and lined inside with
vegetable down. The eggs are white, and never exceed two in number.
Broadly speaking, they resemble each other as closely in habits as in
structure; the greatest differences in habit in the most widely
separated genera being no greater than may be found in two wrens or
sparrows of the same genus.
This persistence of character in humming-birds, both as regards
structure and habit, seems the more remarkable when we consider their
very wide distribution over a continent so varied in its conditions, and
where they range from the lowest levels to the limit of perpetual snow
on the Andes, and from the tropics to the wintry Magellanic district;
also that a majority of genera inhabit very circumscribed areas--these
facts, as Dr. Wallace remarks, clearly pointing to a very high
antiquity.
It is perhaps a law of nature that when a species (or group) fits itself
to a place not previously occupied, and in which it is subject to no
opposition from beings of its own class, or where it attains so great a
perfection as to be able easily to overcome all opposition, the
character eventually loses its original plasticity, or tendency to vary,
since improvement in such a case would be superfluous, and becomes, so
to speak, crystallized in that form which continues thereafter
unaltered. It is, at any rate, clear that while all other birds rub
together in the struggle for existence, the humming-bird, owing to its
aerial life and peculiar manner of seeking its food, is absolutely
untouched by this kind of warfare, and is accordingly as far removed
from all competition with other birds as the solitary savage is removed
from the struggle of life affecting and modifying men in crowded
communities. The lower kind of competition affecting hummingbirds, that
with insects and, within the family, of species with species, has
probably only served to intensify their unique characteristics, and,
perhaps, to lower their intelligence.
Not only are they removed from that indirect struggle for existence
which acts so powerfully on other families, but they are also, by their
habits and the unequalled velocity of their flight, placed out of reach
of that direct war waged on all other small birds by the rapacious
kinds--birds, mammals, and reptiles. One result of this immunity is that
humming-birds are excessively numerous, albeit such slow breeders; for,
as we have seen, they only lay two eggs, and not only so, but the second
egg is often dropped so long after incubation has begun in the first
that only one is really hatched. Yet Belt expressed the opinion that in
Nicaragua, where he observed humming-birds, they out-numbered all the
other birds together. Considering how abundant birds of all kinds are in
that district, and that most of them have a protective colouring and lay
several eggs, it would be impossible to accept such a statement unless
we believed that humming-birds have, practically, no enemies.
Another result of their immunity from persecution is the splendid
colouring and strange and beautiful feather ornaments distinguishing
them above all other birds; and excessive variation in this direction is
due, it seems to me, to the very causes which serve to check variation
in all other directions. In their plumage, as Martin long ago wrote,
nature has strained at every variety of effect and revelled in an
infinitude of modifications. How wonderful their garb is, with colours
so varied, so intense, yet seemingly so evanescent!--the glittering
mantle of powdered gold; the emerald green that changes to velvet black;
ruby reds and luminous scarlets; dull bronze that brightens and burns
like polished brass, and pale neutral tints that kindle to rose and
lilac-coloured flame. And to the glory of prismatic colouring are added
feather decorations, such as the racket-plumes and downy muffs of
Spathura, the crest and frills of Lophornis, the sapphire gorget burning
on the snow-white breast of Oreotrochilus, the fiery tail of Cometes,
and, amongst grotesque forms, the long pointed crest-feathers,
representing horns, and flowing-white beard adorning the piebald
goat-like face of Oxypogon.
Excessive variation in this direction is checked in nearly all other
birds by the need of a protective colouring, few kinds so greatly
excelling in strength and activity as to be able to maintain their
existence without it. Bright feathers constitute a double danger, for
not only do they render their possessor conspicuous, but, just as the
butterfly chooses the gayest flower, so do hawks deliberately single out
from many obscure birds the one with brilliant plumage; but the
rapacious kinds do not waste their energies in the vain pursuit of
hummingbirds. These are in the position of neutrals, free to range at
will amidst the combatants, insulting all alike, and flaunting their
splendid colours with impunity. They are nature's favourites, endowed
with faculties bordering on the miraculous, and all other kinds, gentle
or fierce, ask only to be left alone by them.
CHAPTER XVII.
THE CRESTED SCREAMER.
_(Chalina chavarria.)_
Amongst the feathered notables from all parts of the world found
gathered at the Zoological Gardens in London is the Crested Screamer
from South America. It is in many respects a very singular species, and
its large size, great strength, and majestic demeanour, with the
surprising docility and intelligence it displays when domesticated, give
it a character amongst birds somewhat like that of the elephant amongst
mammals. Briefly and roughly to describe it: in size it is like a swan,
in shape like a lapwing, only with a powerful curved gallinaceous beak.
It is adorned with a long pointed crest and a black neck-ring, the
plumage being otherwise of a pale slaty blue, while the legs and the
naked skin about the eyes are bright red. On each wing, in both sexes,
there are two formidable spurs; the first one, on the second joint, is
an inch and a half long, nearly straight, triangular, and exceedingly
sharp; the second spur, on the last joint, being smaller, broad, and
curved, and roughly resembling in shape and size a lion's claw. There is
another stinking peculiarity. The skin is _emphysematous_--that is,
bloated and yielding to pressure. It crackles when touched, and the
surface, when the feathers are removed, presents a swollen bubbly
appearance; for under the skin there is a layer of air-bubbles extending
over the whole body and even down the legs under the horny tesselated
skin to the toes, the legs thus having a somewhat massive appearance.
And now just a few words about the position of the screamer in
systematic zoology. It is placed in the Family Palamedeidae, which
contains only three species, but about the Order it belongs to there is
much disagreement. It was formerly classed with the rails, and in
popular books of Natural History still keeps its place with them. "Now
the rail-tribe," says Professor Parker, speaking on this very matter,
"has for a long time been burdened (on paper) with a very false army
list. Everything alive that has had the misfortune to be possessed of
large unwieldy feet has been added to this feeble-minded cowardly group,
until it has become a mixed multitude with discordant voices and with
manners and customs having no consonance or relation." He takes the
screamer from the rail-tribe and classes it with the geese (as also does
Professor Huxley), and concludes his study with these words:--"Amongst
living birds there is not one possessing characters of higher interest,
none that I am acquainted with come nearer, in some important points, to
the lizard; and there are parts of the organization which make it very
probable that it is one of the nearest living relations of the
marvellous _Archaeopteryx_"--an intermediate form between birds and
reptiles belonging to the Upper Jurassic period.
The screamer's right to dwell with the geese has not been left
unchallenged. The late Professor Garrod finds that "from considerations
of pterylosis, visceral anatomy, myology, and osteology the screamer
cannot be placed along with the Anserine birds." He finds that in some
points it resembles the ostrich and rhea, and concludes: "It seems
therefore to me that, summing these results, the screamer must have
sprung from the primary avian stock as an independent offshoot at much
the same time as did most of the other important families." This time,
he further tells us, was when there occurred a general break-up of the
ancient terrestrial bird-type, when the acquisition of wings brought
many intruders into domains already occupied, calling forth a new
struggle for existence, and bringing out many special qualities by means
of natural selection.
With this archaeological question I have little to do, and only quote
the above great authorities to show that the screamer appears to be
nearly the last descendant of an exceedingly ancient family, with little
or no relationship to other existing families, and that its pedigree has
been hopelessly lost in the night of an incalculable antiquity. I have
only to speak of the bird as a part of the visible world and as it
appears to the non-scientific lover of nature; for, curiously enough,
while anatomists nave been laboriously seeking for the screamer's
affinities in that "biological field which is as wide as the earth and
deep as the sea," travellers and ornithologists have told us almost
nothing about its strange character and habits.
Though dressed with Quaker-like sobriety, and without the elegance of
form distinguishing the swan or peacock, this bird yet appeals to the
aesthetic feelings in man more than any species I am acquainted with.
Voice is one of its strong points, as one might readily infer from the
name: nevertheless the name is not an appropriate one, for though the
bird certainly does scream, and that louder than the peacock, its scream
is only a powerful note of alarm uttered occasionally, while the notes
uttered at intervals in the night, or in the day-time, when it soars
upwards like the lark of some far-off imaginary epoch in the world's
history when all tilings, larks included, were on a gigantic scale, are.
properly speaking, singing notes and in quality utterly unlike screams.
Sometimes when walking across Regent's Park I bear the resounding cries
of the bird confined there attempting to sing; above the concert of
cranes, the screams of eagles and macaws, the howling of dogs and wolves
and the muffled roar of lions, one can hear it all over the park. But
those loud notes only sadden me. Exile and captivity have taken all
joyousness from the noble singer, and a moist climate has made him
hoarse; the long clear strains are no more, and he hurries through his
series of confused shrieks as quickly as possible, as if ashamed of the
performance. A lark singing high up in a sunny sky and a lark singing in
a small cage hanging against a shady wall in a London street produce
very different effects; and the spluttering medley of shrill and harsh
sounds from the street singer scarcely seems to proceed from the same
kind of bird as that matchless melody filling the blue heavens. There is
even a greater difference in the notes of the crested screamer when
heard in Regent's Park and when heard on the pampas, where the bird
soars upwards until its bulky body disappears from sight, and from that
vast elevation pours down a perpetual rain of jubilant sound.
_Screamer_ being a misnomer, I prefer to call the bird by its vernacular
name of _chaja,_ or _chakar_, a more convenient spelling.
With the chakar the sexes are faithful, even in very large flocks the
birds all being ranged in couples. When one bird begins to sing its
partner immediately joins, but with notes entirely different in quality.
Both birds have some short deep notes, the other notes of the female
being long powerful notes with a trill in them; but over them sounds the
clear piercing voice of the male, ringing forth at the close with great
strength and purity. The song produces the effect of harmony, but,
comparing it with human singing, it is less like a _duo_ than a
_terzetto_ composed of bass, contralto, and soprano.
At certain times, in districts favourable to them, the chakars often
assemble in immense flocks, thousands of individuals being sometimes
seen congregated together, and in these gatherings the birds frequently
all sing in concert. They invariably--though without rising--sing at
intervals during the night, "counting the hours," as the gauchos say;
the first song being at about nine o'clock, the second at midnight, and
the third just before dawn, but the hours vary in different districts.
I was once travelling with a party of gauchos when, about midnight, it
being intensely dark, a couple of chakars broke out singing right ahead
of us, thus letting us know that we were approaching a watercourse,
where we intended refreshing our horses. We found it nearly dry, and
when we rode down to the rill of water meandering over the broad dry bed
of the river, a flock of about a thousand chakars set up a perfect roar
of alarm notes, all screaming together, with intervals of silence after;
then they rose up with a mighty rush of wings. They settled down again a
few hundred yards off, and all together burst forth in one of their
grand midnight songs, making the plains echo for miles around.
There is something strangely impressive in these spontaneous outbursts
of a melody so powerful from one of these large flocks, and though
accustomed to hear these birds from childhood, I have often been
astonished at some new effect produced by a large multitude singing
under certain conditions. Travelling alone one summer day, I carne at
noon to a lake on the pampas called Kakel--a sheet of water narrow
enough for one to see across. Chakars in countless numbers were gathered
along its shores, but they were all ranged in well-defined flocks,
averaging about five hundred birds in each flock. These flocks seemed to
extend all round the lake, and had probably been driven by the drought
from all the plains around to this spot. Presently one flock near me
began singing, and continued their powerful chant for three or four
minutes; when they ceased the next flock took up the strains, and after
it the next, and so on until the notes of the flocks on the opposite
shore came floating strong and clear across the water--then passed away,
growing fainter and fainter, until once more the sound approached me
travelling round to my side again. The effect was very curious, and I
was astonished at the orderly way with which each flock waited its turn
to sing, instead of a general outburst taking place after the first
flock had given the signal. On another occasion I was still more
impressed, for here the largest number of birds I have ever found
congregated at one place all sung together. This was on the southern
pampas, at a place called Gualicho, where I had ridden for an hour
before sunset over a marshy plain where there was still much standing
water in the rushy pools, though it was at the height of the dry season.
This whole plain was covered with an endless flock of chakars, not in
close order, but scattered about in pairs and small groups. In this
desolate spot I found a small rancho inhabited by a gaucho and his
family, and I spent the night with them. The birds were all about the
house, apparently as tame as the domestic fowls, and when I went out to
look for a spot for my horse to feed on, they would not fly away from
me, but merely moved, a few steps out of my path About nine o'clock we
were eating supper in the rancho when suddenly the entire multitude of
birds covering the marsh for miles around burst forth into a tremendous
evening song. It is impossible to describe the effect of this mighty
rush of sound; but let the reader try to imagine half-a-million voices,
each far more powerful than that one which makes itself heard all over
Regent's Park, bursting forth on the silent atmosphere of that dark
lonely plain. One peculiarity was that in this mighty noise, which
sounded louder than the sea thundering on a rocky coast, I seemed to be
able to distinguish hundreds, even thousands, of individual voices.
Forgetting my supper, I sat motionless and overcome with astonishment,
while the air, and even the frail rancho, seemed to be trembling in that
tempest of sound. When it ceased my host remarked with a smile, "We are
accustomed to this, senor--every evening we have this concert." It was a
concert well worth riding a hundred miles to hear. But the chakar
country is just now in a transitional state, and the precise conditions
which made it possible for birds so large in size to form such immense
congregations are rapidly passing away. In desert places, the bird
subsists chiefly on leaves and seeds of aquatic plants; but when the
vast level area of the pampas was settled by man, the ancient stiff
grass-vegetation gave place to the soft clovers and grasses of Europe,
and to this new food the birds took very kindly. Other circumstances
also favoured their increase. They were never persecuted, for the
natives do not eat them, though they are really very good--the flesh
being something like wild goose in flavour. A _higher_ civilization is
changing all this: the country is becoming rapidly overrun with
emigrants, especially by Italians, the pitiless enemies of all
bird-life.
The chakars, like the skylark, love to soar upwards when singing, and at
such times when they have risen till their dark bulky bodies appear like
floating specks on the blue sky, or until they disappear from sight
altogether, the notes become wonderfully etherealized by distance to a
soft silvery sound, and it is then very delightful to listen to them.
It seems strange that so ponderous a fowl with only six feet and a half
spread of wings should possess a power of soaring equal to that of
vultures and eagles. Even the vulture with its marvellous wing power
soars chiefly from necessity, and when its crop is full finds no
pleasure in "scaling the heavens by invisible stairs." The chakar leaves
its grass-plot after feeding and soars purely for recreation, taking so
much pleasure in its aerial exercises that in bright warm weather, in
winter and spring, it spends a great part of the day in the upper
regions of the air. On the earth its air is grave and its motions
measured and majestic, and it rises with immense labour, the wings
producing a sound like a high wind. But as the bird mounts higher,
sweeping round as it ascends, just as vultures and eagles do, it
gradually appears to become more buoyant, describing each succeeding
circle with increasing grace. I can only account for this magnificent
flight, beginning so laboriously, by supposing that the bubble space
under the skin becomes inflated with an air lighter than atmospheric
air, enabling a body so heavy with wings disproportionately short to
float with such ease and evident enjoyment at the vast heights to which
the bird ascends. The heavenward flight of a large bird is always a
magnificent spectacle; that of the chakar is peculiarly fascinating on
account of the resounding notes it sings while soaring, and in which the
bird seems to exult in its sublime power and freedom.
I was once very much surprised at the behaviour of a couple of chakars
during a thunderstorm. On a still sultry day in summer I was standing
watching masses of black cloud coming rapidly over the sky, while a
hundred yards from me stood the two birds also apparently watching the
approaching storm with interest. Presently the edge of the cloud touched
the sun, and a twilight gloom fell on the earth. The very moment the sun
disappeared the birds rose up and soon began singing their long'
resounding notes, though it was loudly thundering at the time, while
vivid flashes of lightning lit the black cloud overhead at short
intervals. I watched their flight and listened to their notes, till
suddenly as they made a wide sweep upwards they disappeared in the
cloud, and at the same moment their voices became muffled, and seemed to
come from an immense distance. The cloud continued emitting sharp
flashes of lightning, but the birds never reappeared, and after six or
seven minutes once more their notes sounded loud and clear above the
muttering thunder. I suppose they had passed through the cloud into the
clear atmosphere above it, but I was extremely surprised at their
fearlessness; for as a rule when soaring birds see a storm coming they
get out of its way, flying before it or stooping to the earth to seek
shelter of some kind, for most living things appear to have a wholesome
dread of thunder and lightning.
When taken young the chakar becomes very tame and attached to man,
showing no inclination to go back to a wild life. There was one kept at
an estancia called Mangrullos, on the western frontier of Buenos Ayres,
and the people of the house gave me a very curious account of it. The
bird was a male, and had been reared by a soldier's wife at a frontier
outpost called La Esperanza, about twenty-five miles from Mangrullos.
Four years before I saw the bird the Indians had invaded the frontier,
destroying the Esperanza settlement and all the estancias for some
leagues around. For some weeks after the invasion the chakar wandered
about the country, visiting all the ruined estancias, apparently in
quest of human beings, and on arriving at Mangrullos, which had not been
burnt and was still inhabited, it settled down at ones and never
afterwards showed any disposition to go away. It was extremely tame,
associating by day with the poultry, and going to roost with them at
night OH a high perch, probably for the sake of companionship, for in a
wild state the bird roosts on the ground. It was friendly towards all
the members of the household except one, a peon, and against this person
from the first the bird always displayed the greatest antipathy,
threatening him with its wings, puffing itself out, and hissing like an
angry goose. The man had a swarthy, beardless face, and it was
conjectured that the chakar associated him in its mind with the savages
who had destroyed its early home.
Close to the house there was a lagoon, never dry, which was frequently
visited by flocks of wild chakars. Whenever a flock appeared the tame
bird would go out to join them; and though the chakars are mild-tempered
birds and very rarely quarrel, albeit so well provided with formidable
weapons, they invariably attacked the visitor with great fury, chasing
him back to the house, and not ceasing their persecutions till the
poultry-yard was reached. They appeared to regard this tame bird that
dwelt with man as a kind of renegade, and hated him accordingly.
Before he had been long at the estancia it began to be noticed that he
followed the broods of young chickens about very assiduously, apparently
taking great interest in their welfare, and even trying to entice them
to follow him. A few newly-hatched chickens were at length offered to
him as an experiment, and he immediately took charge of them with every
token of satisfaction, conducting them about in search of food and
imitating all the actions of a hen. Finding him so good a nurse, large
broods were given to him, and the more the foster-chickens were the
better he seemed pleased. It was very curious to see this big bird with
thirty or forty little animated balls of yellow cotton following him
about, while he moved majestically along, setting down his feet with the
greatest care not to tread on them, and swelling himself up with jealous
anger at the approach of a cat or dog.
The intelligence, docility, and attachment to man displayed by the
chakar in a domestic state, with perhaps other latent aptitudes only
waiting to be developed by artificial selection, seem to make this
species one peculiarly suited for man's protection, without which it
must inevitably perish. It is sad to reflect that all our domestic
animals have descended to us from those ancient times which we are
accustomed to regard as dark or barbarous, while the effect of our
modern so-called humane civilization has been purely destructive to
animal life. Not one type do we rescue from the carnage going on at an
ever-increasing rate over all the globe. To Australia and America, North
and South, we look in vain for new domestic species, while even from
Africa, with its numerous fine mammalian forms, and where England has
been the conquering colonizing power for nearly a century, we take
nothing. Even the sterling qualities of the elephant, the unique beauty
of the zebra, appeal to us in vain. We are only teaching the tribes of
that vast continent to exterminate a hundred noble species they would
not tame. With grief and shame, even with dismay, we call to mind that
our country is now a stupendous manufactory of destructive engines,
which we are rapidly placing in the hands of all the savage and
semi-savage peoples of the earth, thus ensuring the speedy destruction
of all the finest types in the animal kingdom.
CHAPTER XVIII.
THE WOODHEWER FAMILY.
_(Dendrocolaptidae.)_
The South American Tree-creepers, or Woodhewers, as they are sometimes
called, although confined exclusively to one continent, their range
extending from Southern Mexico to the Magellanic islands, form one of
the largest families of the order Passeres; no fewer than about two
hundred and ninety species (referable to about forty-six genera) having
been already described. As they are mostly small, inconspicuous,
thicket-frequenting birds, shy and fond of concealment to excess, it is
only reasonable to suppose that our list of this family is more
incomplete than of any other family of birds known. Thus, in the
southern Plata and north Pata-gonian districts, supposed to be
exhausted, where my observations have been made, and where, owing to the
open nature of the country, birds are more easily remarked than in the
forests and marshes of the tropical region, I have made notes on the
habits of five species, of which I did not preserve specimens, and
which, as far as I know, have never been described and named. Probably
long before the whole of South America has been "exhausted," there will
be not less than four to five hundred Dendrocolaptine species known. And
yet with the exception of that dry husk of knowledge, concerning size,
form and colouration, which classifiers and cataloguers obtain from
specimens, very little indeed--scarcely anything, in fact--is known
about the Tree-creepers; and it would not be too much to say that there
are many comparatively obscure and uninteresting species in Europe, any
one of which has a larger literature than the entire Tree-creeper
family. No separate work about these birds has seen the light, even in
these days of monographs; but the reason of this comparative neglect is
not far to seek. In the absence of any knowledge, except of the most
fragmentary kind, of the life-habits of exotic species, the
monograph-makers of the Old World naturally take up only the most
important groups--i.e. the groups which most readily attract the
traveller's eye with their gay conspicuous colouring, and which have
acquired a wide celebrity. We thus have a succession of splendid and
expensive works dealing separately with such groups as woodpeckers,
trogons, humming-birds, tanagers, king-fishers, and birds of paradise;
for with these, even if there be nothing to record beyond the usual
dreary details and technicalities concerning geographical distribution,
variations in size and markings of different species, &c., the little
interest of the letter-press is compensated for in the accompanying
plates, which are now produced on a scale of magnitude, and with so
great a degree of perfection, as regards brilliant colouring, spirited
attitudes and general fidelity to nature, that leaves little further
improvement in this direction to be looked for. The Tree-creepers, being
without the inferior charm of bright colour, offer no attraction to the
bird-painter, whose share in the work of the pictorial monograph is, of
course, all-important. Yet even the very slight knowledge we possess of
this family is enough to show that in many respects it is one richly
endowed, possessing characters of greater interest to the student of the
instincts and mental faculties of birds, than any of |the gaily-tinted
families I have mentioned.
There is, in the Dendrocolaptidae, a splendid harvest for future
observers of the habits of South American birds: some faint idea of its
richness may perhaps be gathered from the small collection of the most
salient facts known to us about them I have brought together and put in
order in this place. And I am here departing a little from the plan
usually observed in this book, which is chiefly occupied with matters of
personal knowledge, seasoned with a little speculation; but in this case
I have thought it best to supplement my own observations with those of
others [Footnote: Azara; D'Orbigny; Darwin; Bridges; Frazer; Leotaud;
Gaumer; Wallace; Bates; Cunningham; Stolzmann; Jelski; Durnford; Gibson;
Burrows; Doering; White, &c.] who have collected and observed birds in
South America, so as to give as comprehensive a survey of the family as
I could.
It is strange to find a Passerine family, numerous as the Tree-creepers,
uniformly of one colour, or nearly so; for, with few exceptions, these
birds have a brown plumage, without a particle of bright colour. But
although they possess no brilliant or metallic tints, in some species,
as we shall see, there are tints approaching to brightness.
Notwithstanding this family likeness in colour, any person, not an
ornithologist, looking at a collection of specimens comprising many
genera, would hear with surprise and almost incredulity that they all
belonged to one family, so great is the diversity exhibited in their
structure. In size they vary from species smaller than the
golden-crested wren to others larger than the woodcock; but the
differences in size are as nothing compared with those shown in the form
of the beak. Between the minute, straight, conical, tit-like beaks of
the Laptasthenura--a tit in appearance and habits--and the extravagantly
long, sword-shaped bill of Nasica, or the excessively attenuated,
sickle-shaped organ in Xiphorynchus, the divergence is amazing, compared
with what is found in other families; while between these two extremes
there is a heterogeneous assemblage of birds with beaks like creepers,
nuthatches, finches, tyrant-birds, woodpeckers, crows, and even curlews
and ibises. In legs, feet and tails, there are corresponding
differences. There are tails of all lengths and all forms; soft and
stiff, square, acuminated, broad and fan-like, narrow and spine-like,
and many as in the woodpeckers, and used as in that bird to support the
body in climbing. An extremely curious modification is found in
Sittosoma: the tail-feathers in this genus are long and graduated, and
the shafts, projecting beyond the webs at the ends, curve downwards and
form stiff hooks. Concerning the habits of these birds, it has only been
reported that they climb on the trunks of trees: probably they are able
to run vertically up or down with equal facility, and even to suspend
themselves by their feather-hooks when engaged in dislodging insects.
Another curious variation is found in Sylviothorhynchus, a small
wren-like bird and the only member known of the genus, with a tail
resembling that of the lyre-bird, the extravagantly long feathers being
so narrow as to appear almost like shafts destitute of webs. This tail
appears to be purely ornamental.
This extreme variety in structure indicates a corresponding diversity in
habits; and, assuming it to be a true doctrine that habits vary first
and structure afterwards, anyone might infer from a study of their forms
alone that these birds possess a singular plasticity, or tendency to
vary, in their habits--or, in other words, that they are exceptionally
intelligent; and that such a conclusion would be right I believe a study
of their habits will serve to show.
The same species is often found to differ in its manner of life in
different localities. Some species of Xenops and Magarornis, like
woodpeckers, climb vertically on tree-trunks in search of insect prey,
but also, like tits, explore the smaller twigs and foliage at the
extremity of the branches; so that the whole tree, from its root to its
topmost foliage, is hunted over by them. The Sclerurus, although an
inhabitant of the darkest forest, and provided with sharply-curved
claws, never seeks its food on trees, but exclusively on the ground,
among the decaying fallen leaves; but, strangely enough, when alarmed it
flies to the trunk of the nearest tree, to which it clings in a vertical
position, and, remaining silent and motionless, escapes observation by
means of its dark protective colour. The Drymornis, a large bird, with
feet and tail like a woodpecker, climbs on tree-trunks to seek its food;
but also possesses the widely-different habit of resorting to the open
plain, especially after a shower, to feed on larvae and earthworms,
extracting them from a depth of three or four inches beneath the surface
with its immense curved probing beak.
Again, when we consider a large number of species of different groups,
we find that there is not with the Tree-creepers, as with most families,
any special habit or manner of life linking them together; but that, on
the contrary, different genera, and, very frequently, different species
belonging to one genus, possess habits peculiarly their own. In other
families, even where the divergence is greatest, what may be taken as
the original or ancestral habit is seldom or never quite obsolete in any
of the members. This we see, for instance, in the woodpeckers, some of
which have acquired the habit of seeking their food exclusively on the
ground in open places, and even of nesting in the banks of streams. Yet
all these wanderers, even those which have been structurally modified in
accordance with their altered way of life, retain the primitive habit of
clinging vertically to the trunks of trees, although the habit has lost
its use. With the tyrant birds--a family showing an extraordinary amount
of variation--it is the same; for the most divergent kinds are
frequently seen reverting to the family habit of perching on an
elevation, from which to make forays after passing insects, returning
after each capture to the same stand. The thrushes, ranging all over the
globe, afford another striking example. Without speaking of their
nesting habits, their relationship appears in their love of fruit, in
their gait, flight, statuesque attitudes, and abrupt motions.
With the numerous Dendrocolaptine groups, so widely separated and
apparently unrelated, it would be difficult indeed to say which, of
their most striking habits is the ancestral one. Many of the smaller
species live in trees or bushes, and in their habits resemble tits,
warblers, wrens, and other kinds that subsist on small caterpillars,
spiders, &c., gleaned from the leaves and smaller twigs. The Anumbius
nests on trees, but feeds exclusively on the ground in open places;
while other ground-feeders seek their food among dead leaves in dense
gloomy forests. Coryphistera resembles the lark and pipit in its habits;
Cinclodes, the wagtail; Geobates a Saxicola; Limnornis lives in reed
beds growing in the water; Henicornis in reed beds growing out of the
water; and many other ground species exist concealed in the grass on dry
plains; Homorus seeks its food by digging in the loose soil and dead
leaves about the roots of trees; while Geo-sitta, Furnarius, and
Upercerthia obtain a livelihood chiefly by probing in the soil. It would
not be possible within the present limits to mention in detail all the
different modes of life of those species or groups which do not possess
the tree-creeping habit; after them comes a long array of genera in
which this habit is ingrained, and in which the greatly modified feet
and claws are suited to a climbing existence. As these genera comprise
the largest half of the family, also the largest birds in it, we might
expect to find in the tree-creeping the parental habit of the
Dendrocolaptidae, and that from these tropical forest groups have sprung
the widely-diverging thicket, ground, marsh, sea-beach, and
rock-frequenting groups. It happens, however, that these birds resemble
each other only in their climbing feet; in the form of their beaks they
are as wide apart as are nuthatches, woodpeckers, crows, and curlews.
They also differ markedly in the manner of seeking their food. Some dig
like woodpeckers in decayed wood; others probe only in soft rotten wood;
while the humming-bird-billed Xiphorhynchus, with a beak too long and
slender for probing, explores the interior of deep holes in the trunks
to draw out nocturnal insects, spiders, and centipedes from their
concealment. Xiphoco-laptes uses its sword-like beak as a lever,
thrusting it under and forcing up the loose bark; while Dendrornis, with
its stout corvine beak, tears the bark off.
In the nesting habits the diversity is greatest. Some ground species
excavate in the earth like kingfishers, only with greater skill, making
cylindrical burrows often four to five feet deep, and terminating in a
round chamber. Others build a massive oven-shaped structure of clay on a
branch or other elevated site. Many of those that creep on trees nest in
holes in the wood. The marsh-frequenting kinds attach spherical or oval
domed nests to the reeds; and in some cases woven grass and clay are so
ingeniously combined that the structure, while light as a basket, is
perfectly impervious to the wet and practically indestructible. The most
curious nests, however, are the large stick structures on trees and
bushes, in the building and repairing of which the birds are in many
cases employed more or less constantly all the year round. These stick
nests vary greatly in form, size, and in other respects. Some have a
spiral passage-way leading from the entrance to the nest cavity, and the
cavity is in many cases only large enough to accommodate the bird; but
in the gigantic structure of Homorus gutturalis it is so large that, if
the upper half of the nest or dome were removed, a condor could
comfortably hatch her eggs and rear her young in it. This nest is
spherical. The allied Homorus lophotis builds a nest equally large, but
with a small cavity for the eggs inside, and outwardly resembling a
gigantic powder-flask, lying horizontally among the lower branches of a
spreading tree. Pracellodomtis sibila-trix, a bird in size like the
English house sparrow, also makes a huge nest, and places it on the
twigs at the terminal end of a horizontal branch from twelve to fifteen
feet above the ground; but when finished, the weight of the structure
bears down the branch-end to within one or two feet of the surface. Mr.
Barrows, who describes this nest, says: "When other branches of the same
tree are similarly loaded, and other trees close at hand bear the same
kind of fruit, the result is very picturesque." Synallaxis phryganophila
makes a stick nest about a foot in depth, and from the top a tubular
passage, formed of slender twigs interlaced, runs down the entire length
of the nest, like a rain-pipe on the wall of a house, and then becoming
external slopes upward, ending at a distance of two to three feet from
the nest. Throughout South America there are several varieties of these
fruit-and-stem or watering-pot shaped nests; they are not, however, all
built by birds of one genus, while in the genus Synallaxis many species
have no tubular passageways attached to their nests. One species--erythro
thorax--in Yucatan, makes so large a nest of sticks, that the
natives do not believe that so small a bird can be the builder. They say
that when the _tzapatan_ begins to sing, all the birds in the forest
repair to it, each one carrying a stick to add to the structure; only
one, a tyrant-bird, brings two sticks, one for itself and one for the
_urubu_ or vulture, that bird being considered too large, heavy, and
ignorant of architecture to assist personally in the work.
In the southern part of South America, where scattered thorn trees grow
on a dry soil, these big nests are most abundant. "There are plains,"
Mr. Barrows writes, "within two miles of the centre of this town
(Concepcion, Argentine Republic), where I have stood and counted, from
one point within a radius of twenty rods, over two hundred of these
curious nests, varying in size from that of a small pumpkin to more than
the volume of a barrel. Often a single tree will contain half a dozen
nests or more; and, not unfrequently, the nests of several different
species are seen crowding each other out of shape on the same bush or
tree."
It would be a mistake to think that the widely different nesting habits
I have mentioned are found in different genera. I have just spoken of
the big stick nests, with or without passage-ways, of the Synallaxes,
yet the nest of one member of this group is simply a small straight tube
of woven grass, the aperture only large enough to admit the finger, and
open at both ends, so that the bird can pass in and out without turning
round. Another species scoops a circular hollow in the soil, and builds
over it a dome of fine woven grass. It should be mentioned that the
nesting habits of only about fifteen out of the sixty-five species
comprised in this genus are known to us. In the genus Furnarius the
oven-shaped clay structure is known to be made by three species; a
fourth builds a nest of sticks in a tree; a fifth burrows in the side of
a bank, like a kingfisher.
The explanation of the most striking features of the Dendrocolaptidae,
their monotonous brown plumage, diversity of structure, versatile
habits, and the marvellous development of the nest-making instinct which
they exhibit is to be found, it appears to me, in the fact that they are
the most defenceless of birds. They are timid, unresisting creatures,
without strength or weapons; their movements arc less quick and vigorous
than those of other kinds, and their flight is exceedingly feeble. The
arboreal species flit at intervals from one tree to another; those that
frequent thickets refuse to leave their chosen shelter; while those
inhabiting grassy plains or marshes study concealment, and, when forced
to rise, flutter away just above the surface, like flying-fish
frightened from the water, and, when they have gone thirty or forty
yards, dip into the grass or reeds again. Their life is thus one of
perpetual danger in a far greater degree than with other passerine
families, such as warblers, tyrants, finches, thrushes, &c.; while an
exclusively insect diet, laboriously extracted from secret places, and
inability to change their climate, contribute to make their existence a
hard one. It has been with these birds as with human beings, bred in
"misfortune's school," and subjected to keen competition. One of their
most striking characteristics is a methodical, plodding, almost painful
diligence of manner while seeking their food, so that when viewed side
by side with other species, rejoicing in a gayer plumage and stronger
flight, they seem like sober labourers that never rest among holiday
people bent only on enjoyment. That they are able not only to maintain
their existence, but to rise to the position of a dominant family, is
due to an intelligence and adaptiveness exceeding that of other kinds,
and which has been strengthened, and perhaps directly results from the
hard conditions of their life.
How great their adaptiveness and variability must be when we find that
every portion of the South American continent is occupied by them; for
there is really no climate, and no kind of soil or vegetation, which
does not possess its appropriate species, modified in colour, form, and
habits to suit the surrounding conditions. In the tropical region, so
rich in bird life of all kinds, in forest, marsh, and savanna, they are
everywhere abundant--food is plentiful there; but when we go to higher
elevations avd cold sterile deserts, where their companion families of
the tropics dwindle away and disappear, the creepers are still present,
for they are evidently able to exist where other kinds would starve. On
the stony plateaus of the Andes, and on the most barren spots in
Patagonia, where no other bird is seen, there are small species of
Synallaxis, which, in their obscure colour and motions on the ground,
resemble mice rather than birds; indeed, the Quichua name for one of
these Synallaxes is _ukatchtuka,_ or mouse-bird. How different is the
life habit here from what we see in the tropical groups--the large birds
with immense beaks, that run vertically on the trunks of the great
forest trees!
At the extreme southern extremity of the South American continent we
find several species of Cin-clodes, seeking a subsistence like
sandpipers on the beach; they also fly out to sea, and run about on the
floating kelp, exploring the fronds for the small marine animals on
which they live. In the dreary forests of Tierra del Fuego another
creeper, Uxyurus, is by far the commonest bird. "Whether high up or low
down, in the most gloomy, wet, and scarcely penetrable ravines," says
Darwin, "this little bird is to be met with;" and Dr. Cunningham also
relates that in these wintry, savage woods he was always attended in his
walks by parties of these little creepers, which assembled to follow him
out of curiosity.
To birds placed at so great a disadvantage, by a feeble flight and other
adverse circumstances, in the race of life bright colours would
certainly prove fatal. It is true that brown is not in itself a
protective colour, and the clear, almost silky browns and bright
chestnut tints in several species are certainly not protective; but
these species are sufficiently protected in other ways, and can afford
to be without a strictly adaptive colour, so long as they are not
conspicuous. In a majority of cases, however, the colour is undoubtedly
protective, the brown hue being of a shade that assimilates very closely
to the surroundings. There are pale yellowish browns, lined and mottled,
in species living amidst a sere, scanty vegetation; earthy browns, in
those frequenting open sterile or stony places; while the species that
creep on trees in forests are dark brown in colour, and in many cases
the feathers are mottled in such a manner as to make them curiously
resemble the bark of a tree. The genera Lochmias and Sclerurus are the
darkest, the plumage in these birds being nearly or quite black, washed
or tinged with rhubarb yellow. Their black plumage would render them
conspicuous in the sunshine, but they pass their lives in dense tropical
forests, where the sun at noon sheds only a gloomy twilight.
If "colour is ever tending to increase and to appear where it is
absent," as Dr. Wallace believes, then we ought to find it varying in
the direction of greater brightness in some species in a family so
numerous and variable as the Dendrocolaptidae, however feeble and in
need of a protective colouring these birds may be in a majority of
pases. And this in effect we do find. In many of the dark-plumaged
species that live in perpetual shade some parts are a very bright
chestnut; while in a few that live in such close concealment as to be
almost independent of protective colouring, the lower plumage has become
pure white. A large number of species have a bright or nearly bright
guiar spot. This is most remarkable in Synallaxis phryganophila, the
chin being sulphur-yellow, beneath which is a spot of velvet-black, and
on either side a white patch, the throat thus having three strongly
contrasted colours, arranged in four divisions. The presence of this
bright throat spot in so many species cannot very well be attributed to
voluntary sexual selection, although believers in that theory are of
course at liberty to imagine that when engaged in courtship, the male
bird, or rather male and female both, as both sexes possess the spot,
hold up their heads vertically to exhibit it. Perhaps it would be safer
to look on it as a mere casual variation, which, like the exquisitely
pencilled feathers and delicate tints on the concealed sides and under
surfaces of the wings of many species possessing outwardly an obscure
protective colouring, is neither injurious nor beneficial in any way,
either to the birds or to the theory. It is more than probable, however,
that in such small feeble-winged, persecuted birds, this spot of colour
would prove highly dangerous on any conspicuous part of the body. In
some of the more vigorous, active species, we can see a tendency towards
a brighter colouring on large, exposed surfaces. In Auto-malus the tail
is bright satiny rufous; in Pseudo-colaptes the entire under surface is
rufous of a peculiar vivid tint, verging on orange or red; in Magarornis
the bosom is black, and beautifully ornamented with small leaf-shaped
spots of a delicate straw-colour. There are several other very pretty
birds in this homely family; but the finest of all is Thripodectes
flammulatus, the whole body being tortoise-shell colour, the wings and
tail bright chesnut. The powerful tanager-like beak of this species
seems also to show that it has diverged from its timid shade-loving
congeners in another direction by becoming a seed and fruit eater.
Probably the sober and generally protective colouring of the
tree-creepers, even with the variability and adaptiveness displayed in
their habits superadded, would be insufficient to preserve such feeble
birds in the struggle of life without the further advantage derived from
their wonderful nests. It has been said of domed nests that they are a
danger rather than a protection, owing to their large size, which makes
it easy for carnivorous species that prey on eggs and young birds to
find them; while small open nests are usually well concealed. This may
be the case with covered nests made of soft materials, loosely put
together; but it cannot be said of the solid structure the tree-creeper
bnilds, and which, as often as not, the bird erects in the most
conspicuous place it can find, as if, writes Azara, it desired all the
world to admire its work. The annual destruction of adult birds is very
great--more than double that, I believe, which takes place in other
passerine families. Their eggs and young are, however, practically safe
in their great elaborate nests or deep burrows, and, as a rule, they lay
more eggs than other kinds, the full complement being seldom less than
five in the species I am acquainted with, while some lay as many as
nine. Their nests are also made so as to keep out a greater pest than
their carnivorous or egg-devouring enemies--namely, the parasitical
starlings (Molo-thrus), which are found throughout South America, and
are excessively abundant and destructive to birds' nests in some
districts. In most cases, in the big, strong-domed nest or deep burrow,
all the eggs are hatched and all the young reared, the thinning, out
process commencing only after the brood has been led forth into a world
beset with perils. With other families, on the contrary, the greatest
amount of destruction falls on the eggs or fledglings. I have frequently
kept a dozen or twenty pairs of different species--warblers, finches,
tyrants, starlings, &c.--under observation during the breeding season,
and have found that in some cases no young-were reared at all; in other
cases one or two young; while, as often as not, the young actually
reared were only parasitical starlings after all.
I have still to speak of the voice of the tree-creepers, an important
point in the study of these birds; for, though not accounted singers,
some species emit remarkable sounds; moreover, language in birds is
closely related to the social instinct. They seem to be rather solitary
than gregarious; and this seems only natural in birds so timid,
weak-winged, and hard pressed. It would also be natural to conclude from
what has been said concerning their habits that they are comparatively
silent; for, as a rule, vigorous social birds are loquacious and
loud-voiced, while shy solitary kinds preservo silence, except in the
love season. Nevertheless the creepers are loquacious and have loud
resonant voices; this fact, however, does not really contradict a
well-known principle, for the birds possess the social disposition in an
eminent degree, only the social habit is kept down in them by the
conditions of a life which makes solitude necessary. Thus, a large
proportion of species are found to pair for life; and the only
reasonable explanation of this habit in birds--one which is not very
common in the mammalia--is that such species possess the social temper
or feeling, and live in pairs only because they cannot afford to live in
flocks. Strictly gregarious species pair only for the breeding season.
In the creepers the attachment between the birds thus mated for life is
very great, and, as Azara truly says of Anumbius, so fond of each
other's society are these birds, that when one incubates the other sits
at the entrance to the nest, and when one carries food to its young the
other accompanies it, even if it has found nothing to cany. In these
species that live in pairs, when the two birds are separated they are
perpetually calling to each other, showing how impatient of solitude
they are; while even from the more solitary kind, a high-pitched
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