BIRDS.
ADEQUATELY to treat of the intelligence of birds a separate volume would
be required; here it must be enough to deal with this class as I shall
afterwards deal with the Mammalia--namely, by giving an outline sketch
of the more prominent features of their psychology.
_Memory._
The memory of birds is well developed. Thus, although we are much in the
dark on the whole subject of migration--so much so that I reserve its
discussion with all the problems that this presents for a separate
chapter in my next work--we may at least conclude that the return of the
same pair of swallows every year to the same nest must be due to the
animals remembering the precise locality of their nests. Again, Buckland
gives an account of a pigeon which remembered the voice of its mistress
after an absence of eighteen months;[145] but I have not been able to
meet with satisfactory evidence of the memory of a bird enduring for a
longer time than this.
As it is a matter of interest in comparative psychology to trace as far
as possible into detail the similarities of a mental faculty as it
occurs in different groups of animals, and as the faculty of memory
first admits of detailed study in the class which we are now
considering, I shall here devote a paragraph to the facts concerning the
exhibition of memory by birds where its mechanism best admits of being
analysed; I refer to the learning of articulate phrases and tunes by
talking and musical birds. The best observations in this connection with
which I am acquainted are those of Dr. Samuel Wilks, F.R.S., and
therefore I shall quote _in extenso_ the portion of his paper which
refers to the memory of parrots: other portions of this paper I shall
have occasion to quote in my next work:--
When my parrot first came into my possession, several
years ago, it was quite unlettered, and I therefore
had an opportunity of observing the mode in which it
acquired the accomplishment of speech. I was very much
struck with its manner of learning, and the causes for
its speaking on special occasions. The first seemed to
resemble very much the method of children in learning
their lessons, and the second to be due to some
association or suggestion--the usual provocative for
set speeches at all periods of human life. A parrot is
well known to imitate sounds in a most perfect manner,
even to the tone of the voice, besides having a
compass which no human being can approach, ranging
from the gravest to the most acute note. My bird,
though possessing a good vocabulary of words and
sentences, can only retain them for a few months
unless kept constantly in practice by the suggestive
recurrence of some circumstance which causes their
continual utterance. If forgotten, however, they are
soon revived in the memory by again repeating them a
few times, and much more speedily than any new
sentence can be acquired. In beginning to teach the
parrot a sentence, it has to be repeated many times,
the bird all the while listening most attentively by
turning the opening of the ear as close as possible to
the speaker. After a few hours it is heard attempting
to say the phrase, or, I should say, trying to learn
it. It evidently has the phrase somewhere in store,
for eventually this is uttered perfectly, but at first
the attempts are very poor and ludicrous. If the
sentence be composed of a few words, the first two or
three are said over and over again, and then another
and another word added, until the sentence is
complete, the pronunciation at first being very
imperfect, and then becoming gradually more complete,
until the task is accomplished. Thus hour after hour
will the bird be indefatigably working at the
sentence, and not until some days have elapsed will it
be perfect. The mode of acquiring it seems to me
exactly what I have observed in a child learning a
French phrase; two or three words are constantly
repeated, and then others added, until the whole is
known, the pronunciation becoming more perfect as the
repetition goes on. I found also on whistling a
popular air to my parrot that she picked it up in the
same way, taking note by note until the whole
twenty-five notes were complete. Then the mode of
forgetting, or the way in which phrases and airs pass
from its recollection, may be worth remarking. The
last words or notes are first forgotten, so that soon
the sentence remains unfinished or the air only half
whistled through. The first words are the best fixed
in the memory; these suggest others which stand next
to them, and so on till the last, which have the least
hold on the brain. These, however, as I have before
mentioned, can be easily revived on repetition. This
is also a very usual process in the human subject: for
example, an Englishman speaking French will, in his
own country, if no opportunity occur for conversation,
apparently forget it; he no sooner, however, crosses
the Channel and hears the language than it very soon
comes back to him again. In trying to recall poems
learned in childhood or in school days, although at
that period hundreds of lines may have been known, it
is found that in manhood we remember only the two or
three first lines of the 'Iliad,' the 'Æneid,' or the
'Paradise Lost.'[146]
The following is communicated to me by Mr. Venn, of Cambridge, the
well-known logician:--
I had a grey parrot, three or four years old, which
had been taken from its nest in West Africa by those
through whom I received it. It stood ordinarily by the
window, where it could equally hear the front and back
door bells. In the yard, by the back door, was a
collie dog, who naturally barked violently at nearly
all the comers that way. The parrot took to imitating
the dog. After a time I was interested in observing
the discriminative association between the back-door
bell and the dog's bark in the parrot's mind. Even
when the dog was not there, or for any other cause did
not bark, the parrot would constantly bark when the
back-door bell sounded, but never (that I could hear)
when the front-door bell was heard.
This is but a trifle in the way of intelligence, but
it struck me as an interesting analogous case to a law
of association often noticed by writers on human
psychology.
The celebrated parrot that belonged to the Buffon family and of which
the Comte de Buffon wrote, exhibited in a strange manner the association
of its ideas. For he was frequently in the habit of asking himself for
his own claw, and then never failed to comply with his own request by
holding it out, in the same way as he did when asked for his claw by
anybody else. This, however, probably arose, not, as Buffon or his
sister Madame Nadault supposed, from the bird not knowing its own voice,
but rather from the association between the words and the gesture.
According to Margrave, parrots sometimes chatter their phrases in their
dreams, and this shows a striking similarity of psychical processes in
the operations of memory with those which occur in ourselves.
Similarly, Mr. Walter Pollock, writes me of his own parrot:--
In this parrot the sense of association is very
strongly developed. If one word picked up at a former
home comes into its head, and is uttered by it, it
immediately follows this word up with all the other
words and phrases picked up at the same place and
period.
Lastly, parrots not only remember, but recollect; that is to say, they
know when there is a missing link in a train of association, and
purposely endeavour to pick it up. Thus, for instance, the late Lady
Napier told me an interesting series of observations on this point which
she had made upon an intelligent parrot of her own. They were of this
kind. Taking such a phrase as 'Old Dan Tucker,' the bird would remember
the beginning and the end, and try to recollect the middle. For it would
say very slowly, 'Old--old--old--old' (and then very quickly) 'Lucy
Tucker.' Feeling that this was not right, it would try again as before,
'Old--old--old--old--old Bessy Tucker,' substituting one word after
another in the place of the sought-for word 'Dan.' And that the process
was one of truly seeking for the desired word was proved by the fact
that if, while the bird was saying, 'Old--old--old--old,' any one threw
in the word 'Dan,' he immediately supplied the 'Tucker.'
_Emotions._
As regards emotions, it is among birds that we first meet with a
conspicuous advance in the tenderer feelings of affection and sympathy.
Those relating to the sexes and the care of progeny are in this class
proverbial for their intensity, offering, in fact, a favourite type for
the poet and moralist. The pining of the 'love-bird' for its absent
mate, and the keen distress of a hen on losing her chickens, furnish
abundant evidence of vivid feelings of the kind in question. Even the
stupid-looking ostrich has heart enough to die for love, as was the case
with a male in the Rotund of the Jardin des Plantes in Paris, who,
having lost his wife, pined rapidly away. It is remarkable that in some
species--notably pigeons--conjugal fidelity should be so strongly
marked; for this shows, not only what may be called a refinement of
sexual feeling, but also the presence of an abiding image in the mind's
eye of the lover. For instance,--
Referring to the habits of the mandarin duck (a
Chinese species) Mr. Bennett says that Mr. Beale's
aviary afforded a singular corroboration of the
fidelity of the birds in question. Of a pair in that
gentleman's possession, the drake being one night
purloined by some thieves, the unfortunate duck
displayed the strongest marks of despair at her
bereavement, retiring into a corner, and altogether
neglecting food and drink, as well as the care of her
person. In this condition she was courted by a drake
who had lost his mate, but who met with no
encouragement from the widow. On the stolen drake
being subsequently recovered and restored to the
aviary, the most extravagant demonstrations of joy
were displayed by the fond couple; but this was not
all, for, as if informed by his spouse of the gallant
proposals made to her shortly before his arrival, the
drake attacked the luckless bird who would have
supplanted him, beat out his eyes, and inflicted so
many injuries as to cause his death.[147]
Similarly, to give an instance or two with regard to other birds, Jesse
states the following as his own observation:--
A pair of swans had been inseparable companions for
three years, during which time they had reared three
broods of cygnets; last autumn the male was killed,
and since that time the female has separated herself
from all society with her own species; and, though at
the time I am writing (the end of March) the breeding
season for swans has far advanced, she remains in the
same state of seclusion, resisting the addresses of a
male swan, who has been making advances towards
forming an acquaintance with her, either driving him
away, or flying from him whenever he comes near her.
How long she will continue in this state of widowhood
I know not, but at present it is quite evident that
she has not forgotten her former partner.
This reminds me of a circumstance which lately
happened at Chalk Farm, near Hampton. A man, set to
watch a field of peas which had been much preyed upon
by pigeons, shot an old cock pigeon which had long
been an inhabitant of the farm. His mate, around whom
he had for many a year cooed, whom he had nourished
from his own crop, and had assisted in rearing
numerous young ones, immediately settled on the ground
by his side, and showed her grief in the most
expressive manner. The labourer took up the dead bird,
and tied it to a short stake, thinking that it would
frighten away the other depredators. In this
situation, however, the widow did not forsake her
deceased husband, but continued, day after day,
walking slowly round the stick. The kind-hearted wife
of the bailiff of the farm at last heard of the
circumstance, and immediately went to afford what
relief she could to the poor bird. She told me that,
on arriving at the spot, she found the hen bird much
exhausted, and that she had made a circular beaten
track round the dead pigeon, making now and then a
little spring towards him. On the removal of the dead
bird the hen returned to the dove-cote.[148]
As evidence of the intensity of the maternal instinct even in the case
of barren birds, I may quote the following from the naturalist Couch. I
do so because, although the instance is a trivial one, and also one of
frequent occurrence, it is interesting as showing that a deeply rooted
instinct or emotion may assert itself powerfully even in the absence of
what may be termed its natural stimulus or object:--
I was once witness to a curious instance of the
yearning for progeny in a diminutive bantam hen.
There was at this time a nest of the common hen in a
secluded part of the garden, and the parent had been
sitting on its eggs, till compelled by hunger she left
them for a short time. This absence was fatal; for the
bantam had in the meantime found its situation in a
covered recess in the hedge, and I saw her creep into
it with all the triumph of the discoverer of a
treasure. The real mother now returned, and great was
her agony at finding an intruder in her nest. The
expression of her eye and the attitude of her head
were emphatic of surprise at the impudence of the
proceeding. But after many attempts to recover
possession she was compelled to resign her rights, for
the bantam was too resolute to be contended with; and
though its body was not big enough to cover the whole
of the eggs, and thus some of them were not hatched,
yet in due season the pride of this audacious
step-mother was gratified by strutting at the head of
a company of robust chickens, which she passed off
upon the feathered public as a brood of her own.[149]
As evidence of sympathy I shall quote _in extenso_ an interesting case
which has been communicated to me by a young lady, who desires her name
withheld. There are several more or less corroborative cases in the
anecdote-books,[150] so that I have no doubt as to the substantial
accuracy of the account:--
My grandfather had a Swan River gander, which had been
reared near the house, and had consequently attached
himself to the members of the family; so much so that,
on seeing any of them at a distance, he would run to
meet them with all possible demonstrations of delight.
But 'Swanny' was quite an outcast from his own tribe;
and as often as he made humble overtures to the other
geese, so often was he driven away with great
contempt, and on such occasions he would frequently
run to some of his human friends, and laying his head
on their laps, seem to seek for sympathy. At last,
however, he found a friend among his own species. An
old grey goose, becoming blind, was also discarded by
her more fortunate companions, and Swanny lost no
opportunity of recognising this comrade in distress.
He at once took her under his protection and led her
about. When he considered it well for her to have a
swim, he would gently take her neck in his bill, and
thus lead her, sometimes a considerable distance, to
the water's edge. Having fairly launched her, he kept
close by her side, and guided her from dangerous
places by arching his neck over hers, and so turning
her in the right direction. After cruising about a
sufficient time, he would guide her to a convenient
landing-place, and taking her neck in his bill as
before, lead her to _terra firma_ again. When she had
goslings, he would proudly convoy the whole party to
the water-side; and if any ill-fated gosling got into
difficulties in a hole or deep cart-rut, Swanny with
ready skill would put his bill under its body, and
carefully raise it to the level ground.
My grandfather had also another gander who attached
himself to him, and would follow him for hours through
fields and lanes, pausing when he stood still, and
waddling gravely by his side as he proceeded. This
gander was not, like the other, discarded by his kind,
but would leave them any time to walk with his master,
and was exceedingly jealous of any one else who tried
to share this privilege, excepting only his mistress.
On one occasion, a gentleman venturing to place his
hand on my grandfather's arm, the gander flew at him,
and beat him severely with his wings, and it was with
great difficulty that he was induced to let go.
The solicitude which most gregarious birds display when one of their
number is wounded or captured, constitutes strong evidence of sympathy.
As Jesse observes,--
There is one trait in the character of the rook which
is, I believe, peculiar to that bird, and which does
him no little credit; it is the distress which is
exhibited when one of his fellows has been killed or
wounded by a gun while they have been feeding in a
field or flying over it. Instead of being scared away
by the report of the gun, leaving their wounded or
dead companion to his fate, they show the greatest
anxiety and sympathy for him, uttering cries of
distress, and plainly proving that they wish to
render him assistance by hovering over him, or
sometimes making a dart from the air close up to him,
apparently to try and find out the reason why he did
not follow them. . . . I have seen one of my labourers
pick up a rook which he had shot at for the purpose of
putting him up as a scarecrow in a field of wheat, and
while the poor wounded bird was still fluttering in
his hand, I have observed one of his companions make a
wheel round in the air, and suddenly dart past him so
as almost to touch him, perhaps with the last hope
that he might still afford assistance to his
unfortunate mate or companion. Even when the dead bird
has been hung, _in terrorem_, to a stake in the field,
he has been visited by some of his former friends, but
as soon as they found that the case was hopeless, they
have generally abandoned that field altogether.
When one considers the instinctive care with which
rooks avoid any one carrying a gun, and which is so
evident that I have often heard country people remark
that a rook can smell gunpowder, one can more justly
estimate the force of their love or friendship in thus
continuing to hover round a person who has just
destroyed one of their companions with an instrument
the dangerous nature of which they seem fully capable
of appreciating.[151]
The justice of these remarks may be better appreciated in the light of
the following very remarkable observation, as an introduction to which I
have quoted them.
Edward, the naturalist, having shot a tern, which fell winged into the
sea, its companions hovered around the floating bird, manifesting much
apparent solicitude, as terns and gulls always do under such
circumstances. How far this apparent solicitude is real I have often
speculated, as in the analogous case of the crows--wondering whether the
emotions concerned were really those of sympathy or mere curiosity. The
following observation, however, seems to set this question at rest.
Having begun to make preparations for securing the wounded bird, Edward
says: 'I expected in a few moments to have it in my possession, being
not very far from the water's edge, and drifting shorewards with the
wind.' He continues:--
While matters were in this position I beheld, to my
utter astonishment and surprise, two of the unwounded
terns take hold of their disabled comrade, one at
each wing, lift him out of the water, and bear him out
seawards. They were followed by two other birds. After
being carried about six or seven yards, he was let
gently down again, when he was taken up in a similar
manner by the two who had been hitherto inactive. In
this way they continued to carry him alternately,
until they had conveyed him to a rock at a
considerable distance, upon which they landed him in
safety. Having recovered my self-possession, I made
toward the rock, wishing to obtain the prize which had
been so unceremoniously snatched from my grasp. I was
observed, however, by the terns; and instead of four,
I had in a short time a whole swarm about me. On my
near approach to the rock I once more beheld two of
them take hold of the wounded bird as they had done
already, and bear him out to sea in triumph, far
beyond my reach. This, had I been so inclined, I could
no doubt have prevented. Under the circumstances,
however, my feelings would not permit me; and I
willingly allowed them to perform without molestation
an act of mercy, and to exhibit an instance of
affection which man himself need not be ashamed to
imitate.[152]
According to Clavigero,[153] the inhabitants of Mexico utilise the
sympathy of the wild pelican for the procuring of fish. First a pelican
is caught and its wing broken. The bird is then tied to a tree, and
being both in pain and captivity, it utters cries of distress. Other
pelicans are attracted by the cries, and finding their friend in such a
sorry case, their bowels of compassion become moved in a very literal
sense; for they disgorge from their stomachs and pouches the fish which
they have caught, and deposit them within reach of the captive. As soon
as this is done the men, who have been lying in wait concealed, run to
the spot, drive off the friendly pelicans, and secure their fish,
leaving only a small quantity for the use of the captive.
The parrot which belonged to the Buffon family showed much sympathy with
a female servant to whom it was attached when the girl had a sore
finger, which it displayed by its never leaving her sick room, and
groaning as if itself in pain. As soon as the girl got better the bird
again became cheerful.
I shall conclude this brief demonstration of the keen sympathy which may
exist in birds, by quoting the following very conclusive case in the
words of its distinguished observer, Dr. Franklin:[1]--
I have known two parrots, said he, which had lived
together four years, when the female became weak, and
her legs swelled. These were symptoms of gout, a
disease to which all birds of this family are very
subject in England. It became impossible for her to
descend from the perch, or to take her food as
formerly, but the male was most assiduous in carrying
it to her in his beak. He continued feeding her in
this manner during four months, but the infirmities of
his companion increased from day to day, so that at
last she was unable to support herself on the perch.
She remained cowering down in the bottom of the cage,
making, from time to time, ineffectual efforts to
regain the perch. The male was always near her, and
with all his strength aided the feeble attempts of his
dear better half. Seizing the poor invalid by the
beak, or the upper part of the wing, he tried to raise
her, and renewed his efforts several times.
His constancy, his gestures, and his continued
solicitude, all showed in this affectionate bird the
most ardent desire to relieve the sufferings and
assist the weakness of his companion.
But the scene became still more interesting when the
female was dying. Her unhappy spouse moved around her
incessantly, his attention and tender cares redoubled.
He even tried to open her beak to give some
nourishment. He ran to her, then returned with a
troubled and agitated look. At intervals he uttered
the most plaintive cries; then, with his eyes fixed on
her, kept a mournful silence. At length his companion
breathed her last; from that moment he pined away, and
died in the course of a few weeks.[154]
The jealousy of birds is proverbial; and that they also manifest the
kindred passion of emulation, no one can doubt who has heard them
singing against one another. Mr. Bold relates that a mule canary would
always sing at his own image in a mirror, becoming more and more
excited, till he ended by flying in rage against his supposed rival.
The late Lady Napier wrote me, among other 'anecdotes of a grey parrot
left on a long visit to the family of General Sir William Napier, at the
time residing in Germany,' the following graphic description of the
exultation displayed by the bird when it baffled the imitative powers of
its master. The bird was the same as that already mentioned under the
head of 'Memory':--
Sometimes when only two or three were in the room, at
quiet occupations instead of talking, she would utter
at short intervals a series of strong squalls or cries
in an interjectional style, each more strange and
grotesque than the previous one. My father on these
occasions sometimes amused himself by imitating these
cries as she uttered them, which seemed to excite her
ingenuity in the production of them to the uttermost.
As a last resource she always had recourse to a very
peculiar one, which completely baffled him; upon
which, with a loud ha! ha! ha! she made a somersault
round her perch, swinging with her head downwards,
sprung from one part of the cage to another, and
tossed a bit of wood she used as a toy over her head
in the most exulting triumph, repeating at intervals
the inimitable cry, followed by peals of ha! ha! ha!
to the great amusement of all present.
Allied to emulation is resentment, of which the following, communicated
to me by a correspondent, may be taken as an example. If space permitted
I could give confirmatory cases:--
One day the cat and the parrot had a quarrel. I think
the cat had upset Polly's food, or something of that
kind; however, they seemed all right again. An hour or
so after, Polly was standing on the edge of the table;
she called out in a tone of extreme affection, 'Puss,
puss, come then--come then, pussy.' Pussy went and
looked up innocently enough. Polly with her beak
seized a basin of milk standing by, and tipped the
basin and all its contents over the cat; then chuckled
diabolically, of course broke the basin, and half
drowned the cat.
Several strange but mutually corroborative stories seem to show
cherished vindictiveness on the part of storks. Thus, in Captain Brown's
book there occurs an account of a tame stork which lived in the college
yard at Tübingen,--
And in a neighbouring house was a nest, in which other
storks, that annually resorted to the place, used to
hatch their eggs. At this nest, one day in autumn, a
young collegian fired a shot, by which the stork that
was sitting on it was probably wounded, for it did not
fly out of the nest for some weeks afterwards. It was
able, however, to take its departure at the usual time
with the rest of the storks. But in the ensuing spring
a strange stork was observed on the roof of the
college, which, by clapping his wings and other
gestures, seemed to invite the tame stork to come to
him; but, as the tame one's wings were clipped, he was
unable to accept the invitation. After some days the
strange stork appeared again, and came down into the
yard, when the tame one went out to meet him, clapping
his wings as if to bid him welcome, but was suddenly
attacked by the visitor with great fury. Some of the
neighbours protected the tame bird, and drove off the
assailant, but he returned several times afterwards,
and incommoded the other through the whole summer. The
next spring, instead of one stork only, four storks
came together into the yard, and fell upon the tame
one; when all the poultry present--cocks, hens, geese,
and ducks--flocked at once to his assistance, and
rescued him from his enemies. In consequence of this
serious attack, the people of the house took
precaution for the tame stork's security, and he was
no more molested that year. But in the beginning of
the third spring came upwards of twenty storks, which
rushed at once into the yard and killed the tame stork
before either man or any other animal could afford him
protection.
A similar occurrence took place on the premises of a
farmer near Hamburg, who kept a tame stork, and,
having caught another, thought to make it a companion
for the one in his possession. But the two were no
sooner brought together than the tame one fell upon
the other, and beat him so severely that he made his
escape from the place. About four months afterwards,
however, the defeated stork returned with three
others, who all made a combined attack upon the tame
one and killed him.[155]
The curiosity of birds is highly developed, so much so, indeed, that in
this and other countries it is played upon by sportsmen and trappers.
Unfamiliar objects being placed within sight, say, of ducks, the birds
approach to examine them, and fall into the snares which have been
prepared. Similarly, in oceanic islands unfrequented by man, the birds
fearlessly approach to examine the first human beings that they have
seen.
That birds exhibit pride might be considered doubtful if we had to rely
only on the evidence supplied by the display of the peacock, and the
strutting of the turkey-gobbler; for these actions, although so
expressive of this emotion, may not really be due to it. But I think
that the evident pleasure which is taken in achievement by talking birds
can only be ascribed to the emotion in question. These birds regularly
practise their art, and when a new phrase is perfected they show an
unmistakable delight in displaying the result.
Play is exhibited by many species in various ways, and it seems to be
this class of feelings in their most organised form which have led to
the extraordinary instincts of the bower-birds of New South Wales. The
'playhouses' of the animals have been described by Mr. Gould in his
'History of the Birds of New South Wales.' Of course the play-instincts
are here united with those of courtship, which are of such general
occurrence among birds; but I think no one can read Mr. Gould's
description of the bowers and the uses to which they are put without
feeling that the love of sportive play must have been joined with the
sexual instincts in producing the result. But, be this as it may, there
can be no question that these bowers are highly interesting structures,
as furnishing the most unexceptionable evidence of true æsthetic, if not
artistic feeling, on the part of the bird which constructs them; and,
according to Mr. Herbert Spencer, the artistic feelings are
physiologically allied with those of play. It is a matter of importance
to obtain definite proof of an æsthetic sense in animals, because this
constitutes the basis of Mr. Darwin's theory of sexual selection; but as
he has treated the evidence on this subject in so exhaustive a manner, I
shall not enter upon so wide a field further than to point out that the
case of the bower-bird, even if it stood alone, would be amply
sufficient to carry the general conclusion that some animals exhibit
emotions of the beautiful. The following is Mr. Gould's description, _in
extenso_, of the habits of the bird in question:--
The extraordinary bower-like structure, alluded to in
my remarks on the genus, first came under my notice in
the Sydney Museum, to which an example had been
presented by Charles Cox, Esq. . . . On visiting the
cedar bushes of the Liverpool range, I discovered
several of these bowers or playing-houses on the
ground, under the shelter of the branches of the
overhanging trees, in the most retired part of the
forest; they differed considerably in size, some being
a third larger than others. The base consists of an
extensive and rather convex platform of sticks firmly
interwoven, on the centre of which the bower itself is
built. This, like the platform on which it is placed,
and with which it is interwoven, is formed of sticks
and twigs, but of a more slender and flexible
description, the tips of the twigs being so arranged
as to curve inwards and nearly meet at the top; in the
interior the materials are so placed that the forks of
the twigs are always presented outwards, by which
arrangement not the slightest obstruction is offered
to the passage of the birds. The interest of this
curious bower is much enhanced by the manner in which
it is decorated with the most gaily coloured articles
that can be collected, such as the blue tail-feathers
of the Rose-hill and Pennantian parakeets, bleached
bones and shells of snails, &c.; some of the feathers
are inserted among the twigs, while others with the
bones and shells are strewed near the entrances. The
propensity of these birds to fly off with any
attractive object is so well known to the natives that
they always search the runs for any small missing
article that may have been accidentally dropped in the
bush. I myself found at the entrance of one of them a
small neatly worked stone tomahawk of an inch and a
half in length, together with some slips of blue
cotton rag, which the birds had doubtless picked up at
a deserted encampment of the natives.
It has now been clearly ascertained that these curious bowers are merely
sporting-places in which the sexes meet, when the males display their
finery, and exhibit many remarkable actions; and so inherent is this
habit, that the living examples, which have been from time to time sent
to this country, continue it even in captivity.[156] Those belonging to
the Zoological Society have constructed their bowers, decorated and
kept them in repair, for several years. In a letter from the late Mr. F.
Strange, it is said:--
My aviary is now tenanted by a pair of satin-birds,
which for the last two months have been constantly
engaged in constructing bowers. Both sexes assist in
their erection, but the male is the principal workman.
At times the male will chase the female all over the
aviary, then go to the bower, pick up a gay feather or
a large leaf, utter a curious kind of note, set all
his feathers erect, run round the bower, and become so
excited that his eyes appear ready to start from his
head, and he continues opening first one wing and then
another, uttering a low whistling note, and, like the
domestic cock, seems to be picking up something from
the ground, until at last the female goes gently
towards him, when after two turns round her, he
suddenly makes a dash, and the scene ends.[157]
I have said that if this case stood alone it would constitute ample
evidence that some animals possess emotions of the beautiful. But the
case does not stand alone. Certain humming-birds, according to Mr.
Gould, decorate the outsides of their nests 'with the utmost taste; they
instinctively fasten thereon beautiful pieces of flat lichen, the larger
pieces in the middle, and the smaller on the part attached to the
branch. Now and then a pretty feather is intertwined or fastened to the
outer sides, the stem being always so placed that the feather stands out
beyond the surface.' Several other instances might be rendered of the
display of artistic feeling in the architecture of birds; and, as Mr.
Darwin so elaborately shows, there can scarcely be question that these
animals take emotional pleasure in surveying beautiful plumage in the
opposite sex, looking to the careful manner in which the males of many
species display their fine colours to the females. Doubtless the
evidence of æsthetic feeling is much stronger in the case of birds than
it is in that of any other class; but if this feeling is accepted as a
sufficient cause, through sexual selection, of natural decoration in the
members of this class, we are justified in attributing to sexual
selection, and so to æsthetic feeling, natural decoration in other
classes, at least as low down in the scale as the Articulata. But, as I
have said, Mr. Darwin has dealt with this whole subject in so exhaustive
a manner that it is needless for me to enter upon it further than to say
in general terms, that whatever we may think of his theory of sexual
selection, his researches have unquestionably proved the existence of an
æsthetic sense in animals.
The same fact appears to be shown in another way by the fondness of
song-birds for the music of their mates. There can be no doubt that male
birds charm their females with their strains, and that this, in fact, is
the reason why song in birds has become developed. Of course it may be
said that the vocal utterances of birds are not always, or even
generally, musical; but this does not affect the fact that birds find
some æsthetic pleasure in the sounds which they emit; it only shows that
the standard of æsthetic taste differs in different species of birds as
it does in different races of men. Moreover, the pleasure which birds
manifest in musical sounds is not always restricted to the sounds which
they themselves produce. Parrots seem certainly to take delight in
hearing a piano play or a girl sing; and the following instance,
published by the musician John Lockman, reveals in a remarkable manner
the power of distinguishing a particular air, and of preferring it above
others. He was staying at the house of a Mr. Lee in Cheshire, whose
daughter used to play; and whenever she played the air of 'Speri si'
from Handel's opera of 'Admetus,' a pigeon would descend from an
adjacent dovecot to the window of the room where she sat, 'and listen to
the air apparently with the most pleasing emotions,' always returning to
the dovecot immediately the air was finished. But it was only this one
air that would induce the bird to behave in this way.[158]
_Special Habits._
Under this heading we shall have a number of facts to consider, which
are more or less of a disconnected character.
Taking first those special habits connected with the procuring of food,
we may notice the instinct manifested by blackbirds and thrushes of
conveying snails to considerable distances in order to hammer and break
their shells against what may happen to be the nearest stone,[159] and the
still more clever though somewhat analogous instinct exhibited by
certain gulls and crows of flying with shell-fish to a considerable
height and letting them fall upon stones for the purpose of smashing
their shells.[160] Both these instincts manifest a high degree of
intelligence, either on the part of the birds themselves, or on that of
their ancestors; for neither of these instincts can be regarded as due
to originally accidental adjustments favoured and improved by natural
selection; they must at least originally have been intelligent actions
purposely designed to secure the ends attained.
An interesting instinct is that of piracy, which in the animal kingdom
reaches its highest or most systematic development among the birds. It
is easy to see how it may be of more advantage to a species of strong
bird that its members should become parasitic on the labours of other
species than that they should forage for themselves, and so there is no
difficulty in understanding the development of the plundering instinct
by natural selection. We find all stages of this development among the
sea-birds. Thus the gulls, although usually self-foragers, will, as I
have often observed, congregate in enormous numbers where the guillemots
have found a shoal of fish. Resting on or flying over the surface of
the water, the gulls wait till a guillemot comes to the surface with a
fish, and then wrest the latter from the beak of the former. In the
robber-tern this instinct has proceeded further, so that the animal
gains its subsistence entirely by plunder of other terns. I have often
observed this process, and it is interesting that the common tern well
knows the appearance of the robber; for no sooner does a robber-tern
come up than the greatest consternation is excited among a flock of
common terns, these flying about and screaming in a frantic manner. The
white-headed eagle has also developed the plundering instinct in great
perfection, as is shown by the following graphic account of Audubon:--
During spring and summer, the white-headed eagle, to
procure sustenance, follows a different course, and
one much less suited to a bird apparently so well able
to supply itself without interfering with other
plunderers. No sooner does the first hawk make its
appearance along the Atlantic shore, or around the
numerous and large rivers, than the eagle follows it,
and, like a selfish oppressor, robs it of the
hard-earned fruits of its labour. Perched on some tall
summit, in view of the ocean or of some watercourse,
he watches every motion of the osprey while on the
wing. When the latter rises from the water, with a
fish in its grasp, forth rushes the eagle in pursuit.
He mounts above the fish-hawk, and threatens it by
actions well understood; when the latter, fearing
perhaps that its life is in danger, drops its prey. In
an instant the eagle, accurately estimating the rapid
descent of the fish, closes its wings, follows it with
the swiftness of thought, and the next moment grasps
it. The prize is carried off in silence to the woods,
and assists in feeding the ever-hungry brood of the
eagle.
The frigate pelican is likewise a professional thief, and attacks the
boobies not only to make them drop the fish which they have newly
caught, but also to disgorge those which are actually in their stomachs.
The latter process is effected by strong punishment, which they continue
until the unfortunate booby yields up its dinner. The punishment
consists in stabbing the victim with its powerful beak. Catesby and
Dampier have both observed and described these habits, and it seems from
their account that the plunderer may either commit highway robbery in
the air, or lie in wait for the boobies as they return to rest.
In antithesis to this habit of plundering other birds I may quote the
following from 'Nature' (July 20, 1871), to show that the instinct of
provident labour, so common among insects and rodents, is not altogether
unrepresented in birds:--
The ant-eating woodpecker (_Melanerpes formicivorus_),
a common Californian species, has the curious and
peculiar habit of laying up provision against the
inclement season. Small round holes are dug in the
bark of the pine and oak, into each of which is
inserted an acorn, and so tightly is it fitted or
driven in, that it is with difficulty extricated. The
bark of the pine trees, when thus filled, presents at
a short distance the appearance of being studded with
nails.
The following may also be quoted:--
It is the nature of this bird (guillemot), as well as
of most of those birds which habitually dive to take
their prey, to perform all their evolutions under
water with the aid of their wings; but instead of
dashing at once into the midst of the terrified group
of small prey, by which only a few would be captured,
it passes round and round them, and so drives them
into a heap; and thus has an opportunity of snatching
here one and there another as it finds it convenient
to swallow them; and if any one pushes out to escape,
it falls the first prey of the devourer. The manner in
which this bird removes the egg of a gull or hen to
some secure place to be devoured, when compared with
that in which a like conveyance is made by the parent
for the safety of its future progeny, affords a
striking manifestation of the difference between
appetite and affection. When influenced by affection,
the brittle treasure is removed without flaw or
fracture, and is replaced with tender care; but the
plunderer at once plunges his bill into its substance,
and carries it off on its point.[161]
Speaking of the feeding habits of the lapwing, Jesse says:--
When the lapwing wants to procure food, it seeks for a
worm's cast, and stamps the ground by the side of it
with its feet. After doing this for a short time, the
bird waits for the issue of the worm from its hole,
which, alarmed at the shaking of the ground,
endeavours to make its escape, when it is immediately
seized, and becomes the prey of the ingenious bird.
The lapwing also frequents the haunts of moles, which,
when in pursuit of worms on which they feed, frighten
them, and the worm, in attempting to escape, comes to
the surface of the ground, when it is seized by the
lapwing.[162]
Again,--
A lady of Dr. E. Darwin's acquaintance saw a little
bird repeatedly hop on a poppy stem, and shake the
head with his bill, till many seeds were scattered,
when it settled on the ground and picked up the
seeds.[163]
It is a matter of common remark that in countries where vultures abound,
these birds rapidly 'gather together where the carcass is,' although
before the death of their prey no bird was to be seen in the sky. The
question has always been asked whether the vultures are guided to the
carcass by their sense of smell or by that of sight; but this question
is really no longer an open one. When Mr. Darwin was at Valparaiso he
tried the following experiment. Having tied a number of condors in a
long row, and having folded up a piece of meat in paper, he walked
backwards and forwards in front of the row, carrying the meat at a
distance of three yards from them, 'but no notice whatever was taken.'
He then threw the meat upon the ground, within one yard of an old male
bird; 'he looked at it for a moment with attention, but then regarded it
no more.' With a stick he next pushed the meat right under the beak of
the bird. Then for the first time the bird smelled it, and tore open the
paper 'with fury, and at the same moment every bird in the long row
began struggling and flapping its wings.'[164] Thus there can be no doubt
that vultures do not depend on their sense of smell for finding carrion
at a distance. Nor is it mysterious why they should find it by their
sense of sight. If over an area of many square miles there are a number
of vultures flying as they do at a very high elevation, and if one of
the number perceives a carcass and begins to descend, the next adjacent
vultures would see the descent of the first one, and follow him as a
guide, while the next in the series would follow these in the same way,
and so on.
Coming now to special instincts relating to incubation and the care of
offspring, a correspondent writes:--
Last spring I had a pair of canaries, in an ordinary
breeding cage (with two small boxes for nests in a
compartment at one end). In due course the first egg
was laid, which I inspected through the little door
made for that purpose. The next day I looked again;
still only one egg, and so for four or five days. It
being evident, from the appearance of the hen, that
there were more eggs coming, and as she seemed in good
health, I supposed she might have broken some; and I
took out the box, and examined it carefully for the
shells (but without pulling the nest to pieces), and
found nothing, until towards the beginning of another
week I went to take the one egg away, as the hen
seemed preparing to sit upon it. There were two eggs!
The next morning, to my surprise, she was sitting upon
six eggs! She must therefore have buried four of them
in the four corners of the box, and so deep that I had
been unable to find them. At first I thought that she
had done so merely from dislike at their being looked
at, but on reflection it has occurred to me that she
did it that all might be hatched at the same time (as
they subsequently were); for she was perfectly tame,
and would almost suffer herself to be handled when on
her nest. Wild birds never seem to conceal their eggs
before sitting; but then (having more amusements than
cage birds) they do not revisit their eggs after
laying, until they have laid their number, whereas a
caged bird, having nothing to divert her attention
from her nest, often sits on it the greater part of
the day.
I am not aware that this curious display of forethought on the part of a
caged bird has been hitherto recorded, and seeing, as my correspondent
points out, that it has reference to the changed conditions of life
brought about by domestication, it may be said to constitute the first
step in the development of a new instinct, which, if the conditions were
of sufficiently long continuance, might lead to an important and
permanent change of the ancestral instinct.
I have several interesting facts, also communicated to me by
correspondents, similarly relating to individual variations of the
ancestral instinct of incubation in order to meet the requirements of a
novel environment. Thus Mr. J. F. Fisher tells me that while he was a
commander in the East India trade he always took a quantity of fowls to
sea for food. The laying-boxes being in a confined space, the hens used
to quarrel over their occupancy; and one of the hens adopted the habit
of removing the 'nest-eggs' which Mr. Fisher placed in one of the boxes
to another box of the same kind not very far away. He watched the
process through a chink of a door, and 'saw her curl her neck round the
egg, thus forming a cup by which she lifted the egg,' and conveyed it to
the other box. He adds:--
I can give no information as to the more recondite
question _why_ the egg was removed, or the fastidious
preference of the one box over the other, or the
inventive faculty that suggested the neck as a
makeshift hand; but from the despatch with which she
effected the removal of the egg in the case I saw, I
have no doubt that this hen was the one which had
performed the feat so often before.
The explanation of the preference shown for the one box over the other
may, I think, be gathered from another part of my correspondent's
letter, for he there mentions incidentally that the box in which he
placed the nest-egg, and from which the hen removed it, was standing
near a door which was usually open, and thus situated in a more exposed
position than the other box. But be this as it may, considering that
among domestic fowls the habit of conveying eggs is not usual, such
isolated cases are interesting as showing how instincts may originate.
Jesse gives an exactly similar case ('Gleanings,' vol. i., p. 149) of
the Cape goose, which removed eggs from a nest attacked by rats, and
another case of a wild duck doing the same.
In the same connection, and with the same remarks, I may quote the
following case in which a fowl adopted the habit of conveying, not her
eggs, but her young chickens. I quote it from Houzeau ('Journ.,' i., p.
332), who gives the observation on the authority of his brother as
eye-witness. The fowl had found good feeding-ground on the further side
of a stream four metres wide. She adopted the habit of flying across
with her chickens upon her back, taking one chicken on each journey. She
thus transferred her whole brood every morning, and brought them back in
a similar way to their nest every evening. The habit of carrying young
in this way is not natural to Grallinaceæ, and therefore this particular
instance of its display can only be set down as an intelligent
adjustment by a particular bird.
Similarly, a correspondent (Mr. J. Street) informs me of a case in which
a pair of blackbirds, after having been disturbed by his gardener
looking into their nest at their young, removed the latter to a distance
of twenty yards, and deposited them in a more concealed place.
Partridges are well known to do this, and similarly, according to
Audubon, the goatsucker, when its nest is disturbed, removes its eggs to
another place, the male and female both transporting eggs in their
beaks.[165]
Still more curiously, a case is recorded in 'Comptes Rendu' (1836) of a
pair of nightingales whose nest was threatened by a flood, and who
transported it to a safe place, the male and the female bearing the nest
between them.
Now, it is easy to see that if any particular bird is intelligent
enough, as in the cases quoted, to perform this adjustive action of
conveying young--whether to feeding-grounds, as in the case of the hen,
or from sources of danger, as in the case of partridges, blackbirds, and
goatsuckers--inheritance and natural selection might develop the
originally intelligent adjustment into an instinct common to the
species. And it so happens that this has actually occurred in at least
two species of birds--viz., the woodcock and wild duck, both of which
have been repeatedly observed to fly with their young upon their backs
to and from their feeding-ground.
Couch gives some facts of interest relating to the mode of escape
practised by the water-rail, swan, and some other aquatic birds. This
consists in sinking under water, with only the bill remaining above the
surface for respiration. When the swan has young, she may sink the head
quite under water in order to allow the young to mount on it, and so be
carried through even rapid currents.
The same author remarks that--
Many birds will carefully remove the meetings of the
young from the neighbourhood of their nests, in order
not to attract the attention of enemies; for while we
find that birds which make no secret of their
nesting-places are careless in such matters, the
woodpecker and the marsh tit in particular are at
pains to remove even the chips which are made in
excavating the cavities where the nests are placed,
and which might lead an observer to the sacred spot.
Similarly, Jesse observes:--
The excrement of the young of many birds who build
their nests without any pretensions to concealment,
such as the swallow, crow, &c., may at all times be
observed about or under the nest; while that of some
of those birds whose nests are more industriously
concealed is conveyed away in the mouths of the parent
birds, who generally drop it at a distance of twenty
or thirty yards from the nest. Were it not for this
precaution, the excrement itself, from its
accumulation, and commonly from its very colour, would
point out the place where the young were concealed.
When the young birds are ready to fly, or nearly so,
the old birds do not consider it any longer necessary
to remove the excrement.
Sir H. Davy gives an account of a pair of eagles which he saw on Ben
Nevis teaching their young ones to fly; and every one must have observed
the same thing among commoner species of birds. The experiments of
Spalding, however, have shown that flying is an instinctive faculty; so
that when he reared swallows from the nest and liberated them only after
they were fully fledged, they flew well immediately on being liberated.
Therefore, the 'teaching to fly' by parent birds must be regarded as
mere encouragement to develop instinctive powers, which in virtue of
this encouragement are probably developed sooner than would otherwise be
the case.
A few observations may here be offered on some habits which do not fall
under any particular heading.
The habit which many small birds display of mobbing carnivorous ones is
probably due to a desire to drive off the enemy, and perhaps also to
warn friends by the hubbub. It may therefore perhaps be regarded as a
display of concerted action, of which, however, we shall have better
evidence further on. I have seen a flock of common terns mob a pirate
tern, which shows that this combined action may be directed as much
against robbery as against murder. Couch says he has seen blackbirds
mobbing a cat which was concealed in a bush, and here the motive would
seem to be that of warning friends rather than that of driving away the
enemy.
I have observed among the sea-gulls at the Zoological Gardens a curious
habit, or mode of challenge. This consists in ostentatiously picking up
a small twig or piece of wood, and throwing it down before the bird
challenged, in the way that a glove used to be thrown down by the old
knights. I observed this action performed repeatedly by several
individuals of the glaucous and black-back species in the early
spring-time of the year, and so it probably has some remote connection
with the instinct of nest-building.
_Nidification._
In connection with the habits and instincts peculiar to certain species
of birds, I may give a short account of the more remarkable kinds of
nidification that are met with in this class of animals. As the account
must necessarily be brief, I shall only mention the more interesting of
the usual types.
Petrels and puffins make their nests in burrows which they excavate in
the earth. The great sulphur mountain in Guadaloupe is described by
Wasser as 'all bored like a rabbit warren with the holes that these imps
(_i.e._ petrels) excavate.' In the case of the puffin it is the male
that does the work of burrowing. He throws himself upon his back in the
tunnel which he has made, and digs it longer and longer with his broad
bill, while casting out the mould with his webbed feet. The burrow when
finished has several twists and turns in it, and is about ten feet deep.
If a rabbit burrow is available, the puffin saves himself the trouble of
digging by taking possession of the one already made. The kingfisher and
land-martin also make their nests in burrows.
Certain auks lay their single egg on the bare rock while the stone
curlew and goatsucker deposit theirs on the bare soil, returning,
however, year after year to the same spot. Ostriches scrape holes in the
sand to serve as extemporised nests for their eggs promiscuously
dropped, which are then buried by a light coating of sand, and incubated
during the day by the sunbeams, and at night by the male bird. Sometimes
a number of female ostriches deposit their eggs in a common nest, and
then take the duty of incubation by turns. Similarly, gulls, sandpipers,
plovers, &c., place their eggs in shallow pits hollowed out of the soil.
The kingfisher makes a bed of undigested fish-bones ejected as pellets
from her stomach, and 'some of the swifts secrete from their salivary
glands a fluid which rapidly hardens as it dries on exposure to the air
into a substance resembling isinglass, and thus furnish the "edible
birds' nests" that are the delight of the Chinese epicures.'[166]
The house-martin builds its nest of clay, which it sticks upon the face
of a wall, and renders more tenacious by working into it little bits of
straw, splinters of wood, &c. According to Mr. Gilbert White:--
That this work may not, while it is soft and green,
pull itself down by its own weight, the provident
architect has prudence and forbearance enough not to
advance her work too fast; but by building only in the
morning, and by dedicating the rest of the day to food
and amusement, gives it sufficient time to dry and
harden. About half an inch seems a sufficient layer
for a day. Thus careful workmen, when they build mud
walls (informed at first perhaps by these little
birds), raise but a moderate layer at a time, and then
desist, lest the work should become top-heavy, and
ruined by its own weight. By this method, in about ten
or twelve days is formed a hemispheric nest, with a
small aperture towards the top, strong, compact, and
warm, and perfectly fitted for all the purposes for
which it was intended.
Other birds build in wood. The tomtit and the woodpecker excavate a hole
in a tree, and carefully carry away the chips, so as not to give any
indication of the whereabouts of their nests. Wilson says that the
American woodpecker makes an excavation five feet in depth, of a
tortuous form, to keep out wind and rain.
The orchard starling suspends its nest from the branches of a tree, and
uses for its material tough kinds of grass, the blades of which it
weaves together. Wilson found one of these blades to be thirteen inches
long, and to be woven in and out thirty-four times.
We may next notice the weaver (_Ploceus textor_) and tailor (_Prinia_,
_Orthotomus_, and _Sylvia_). The former intertwines slender leaves of
grass so as to produce a web sufficiently substantial for the protection
of its young. The tailor-birds sew together leaves wherewith to make
their nests, using for the purpose cotton and thread where they can find
it, and natural vegetable fibres where they cannot obtain artificial.
Colonel Sykes says that he has found the threads thus used for sewing
knotted at the ends.[167]
Forbes saw the tailor-bird of the East Indies constructing its nest, and
observed it to choose a plant with large leaves, gather cotton which it
regularly spun into a thread by means of its bill and claws, and then
sew the leaves together, using its beak as a needle, or rather awl.
This instinct is rendered particularly interesting to evolutionists from
the fact that it is exhibited by three distinct genera. For, as the
instinct is so peculiar and unique, it is not likely to have originated
independently in the three genera, but must be regarded as almost
certainly derived from a common ancestral type--thus showing that an
instinct may be perpetuated unaltered after the differentiation of
structure has proceeded beyond a specific distinction. The genus
_Sylvia_ inhabits Italy, the other two inhabit India. _Sylvia_ uses for
thread spiders' web collected from the egg-pouches, which is stitched
through holes made in the edges of leaves, presumably with the beak.
The baya bird of India 'hangs its pendulous dwelling from a projecting
bough, twisting it with grass into a form somewhat resembling a bottle
with a prolonged neck, the entrance being inverted, so as to baffle the
approaches of its enemies, the tree snakes and other reptiles.'
Sir E. Tennent, from whom this account is taken, adds:--
The natives assert that the male bird carries
fire-flies to the nest, and fastens them to its sides
by particles of soft mud. Mr. Layard assures me that
although he has never succeeded in finding the
fire-fly, the nest of the male bird (for the female
occupies another during incubation) invariably
contains a patch of mud on each side of the perch.
Dr. Buchanan confirms the report of the natives here alluded to, and
says:--
At night each of the habitations is lighted up by a
fire-fly stuck on the top with a bit of clay. The nest
consists of two rooms; sometimes there are three or
four fire-flies, and their blaze in the little cells
dazzles the eyes of the bats, which often kill the
young of these birds.
While this work is passing through the press I meet with the following,
which appears to refer to some independent, and therefore corroborative
observation concerning the above-stated fact, and in any case is worth
adding, on account of the observation concerning the rats, which, if
trustworthy, would furnish a sufficient reason for the instinct of the
birds. The extract is taken from a letter to 'Nature' (xxiv., p. 165),
published by Mr. H. A. Severn:
I have been informed on safe authority that the Indian
bottle-bird protects his nest at night by sticking
several of these glow-beetles around the entrance by
means of clay; and only a few days back an intimate
friend of my own was watching three rats on a roof
rafter of his bungalow when a glow-fly lodged very
close to them; the rats immediately scampered off.
The Talegallus of Australia is, in the opinion of Gould,--
Among the most important of the ornithological
novelties which the exploration of Western and
Southern Australia has unfolded to us, and this from
the circumstance of its not hatching its own eggs,
which, instead of being incubated in the usual way,
are deposited in mounds of mixed sand and herbage, and
there left for the heating of the mass to develop the
young, which, when accomplished, force their way
through the sides of the mound, and commence an active
life from the moment they see the light of day.[168]
Sir George Grey measured one of these mounds, and found it to be
'forty-five feet in circumference, and if rounded in proportion on the
top (it being at the time unfinished) would have been full five feet
high.' The heat round the eggs was taken to be 89°.
A curious aberration of the nest-building instinct is sometimes shown by
certain birds--particularly the common wren--which consists in building
a supernumerary nest. That is to say, after one nest is completed,
another is begun and finished before the eggs are laid, and the first
nest is not used, though sometimes it is used in preference to the
second.
As showing at once the eccentricity which birds sometimes display in the
choice of a site, and also the determination of certain birds to return
to the same site in successive years, I may allude to the case published
by Bingley, of a pair of swallows which built their nest upon the wings
and body of a dead owl, which was hanging from the rafters of a barn,
and so loosely as to sway about with every gust of wind. The owl with
the nest upon it was placed as a curiosity in the museum of Sir Ashton
Lever, and he directed that a shell should be hung upon the rafters in
the place which had been previously occupied by the dead owl. Next year
the swallows returned and constructed their new nest in the cavity of
the shell.[169]
The following is quoted from Thompson's 'Passions of Animals,' p. 205:--
The sociable grosbeak of Africa is one of the few
instances of birds living in community and uniting in
constructing one huge nest for the whole society. L.
Valiant's account has been fully confirmed by other
travellers. He says: 'I observed on the way a tree
with an enormous nest of these birds, which I have
called republicans; and as soon as I arrived at my
camp I despatched a few men with a waggon to bring it
to me, that I might open and examine the hive. When it
arrived, I cut it in pieces with a hatchet, and saw
that the chief portion of the structure consisted of a
mass of Boshman's grass, without any mixture, but so
compact and firmly basketed together as to be
impenetrable to the rain. This is the commencement of
the structure, and each bird builds its particular
nest under this canopy. But the nests are formed only
beneath the eaves, the upper surface remaining void,
without, however, being useless; for as it has a
projecting rim, and is a little inclined, it serves to
let the water run off, and preserves each little
dwelling from the rain. Figure to yourself a huge
irregular sloping roof, all the eaves of which are
covered with nests, crowded one against another, and
you will have a tolerably accurate idea of these
singular edifices. Each individual nest is three or
four inches in diameter, which is sufficient for the
bird; but, as they are all in contact with one another
around the eaves, they appear to the eye to form but
one building, and are distinguishable from each other
only by a little external aperture which serves as an
entrance to the nest; and even this is sometimes
common to three different nests, one of which is
situated at the bottom and the other two at the sides.
This large nest, which was one of the most
considerable I had anywhere seen in the course of my
journey, contained 320 inhabited cells, which,
supposing a male and female to each, would form a
society of 640 individuals; but as these birds are
polygamous, such a calculation would not be exact.'
The following is quoted from Couch ('Illustrations of Instinct,' p. 227
_et seq._):--
Mr. Waterton says there is a peculiarity in the
nidification of the domestic swan too singular to be
passed over without notice. At the time it lays its
first egg the nest which it has prepared is of very
moderate size; but as incubation proceeds we see it
increase vastly in height and breadth. Every soft
material, such as pieces of grass and fragments of
sedges, is laid hold of by the sitting swan as they
float within her reach, and are added to the nest.
This work of accumulation is performed by her during
the entire period of incubation, be the weather wet or
dry, settled or unsettled; and it is perfectly
astonishing to see with what assiduity she plies her
work of aggrandisement to a nest already sufficient
in strength and size to answer every end. My swans
generally form their nest on an island quite above the
reach of a flood; and still the sitting bird never
appears satisfied with the quantity of materials which
are provided for her nest. I once gave her two huge
bundles of oaten straw, and she performed her work of
apparent supererogation by applying the whole of it to
her nest, already very large, and not exposed to
destruction had the weather become ever so rainy.
This same author continues:--
It is probable that this disposition to accumulation,
in its general bearing, has reference to heat rather
than the flood; but that the wild swan has a foresight
regarding danger, and a quick perception as to the
means of securing safety, appears from an instance
mentioned by Captain Parry, in his Northern voyage.
When everything was deeply involved in ice, the
voyagers were obliged to pay much attention to discern
whether they were travelling over water or land; but
some birds, which formed their nest at no great
distance from the ships, were under no mistake in so
important a matter; and when the thaw took place it
was seen that the nest was situated on an island in
the lake.
The following cases are likewise taken from Couch (_loc. cit._, p.
225):--
This swan was eighteen or nineteen years old, had
brought up many broods, and was highly valued by the
neighbours. She exhibited, some eight or nine years
past, one of the most remarkable powers of instinct
ever recorded. She was sitting on four or five eggs,
and was observed to be very busy in collecting weeds,
grasses, &c., to raise her nest; a farming man was
ordered to take down half a load of haulm, with which
she most industriously raised her nest and the eggs
two feet and a half; that very night there came down a
tremendous fall of rain, which flooded all the
malt-shops and did great damage. Man made no
preparation, the bird did; instinct prevailed over
reason. Her eggs were above, and only just above, the
water.
During the early part of the summer of 1835, a pair of
water-hens built their nest by the margin of the
ornamental pond at Bell's Hill, a piece of water of
considerable extent, and ordinarily fed by a spring
from the height above, but into which the contents of
another large pond can occasionally be admitted. This
was done while the female was sitting; and as the nest
had been built when the water level stood low, the
sudden influx of this large body of water from the
second pond caused a rise of several inches, so as to
threaten the speedy immersion and consequent
destruction of the eggs. This the birds seem to have
been aware of, and immediately took precautions
against so imminent a danger; for when the gardener,
upon whose veracity I can safely rely, seeing the
sudden rise of the water, went to look after the nest,
expecting to find it covered and the eggs destroyed,
or at least forsaken by the hen, he observed, whilst
at a distance, both birds busily engaged about the
brink where the nest was placed; and when near enough
he clearly perceived that they were adding, with all
possible despatch, fresh materials to raise the fabric
beyond the level of the increased contents of the
pond; and that the eggs had by some means been removed
from the nest by the birds, and were then deposited
upon the grass about a foot or more from the margin of
the water. He watched them for some time, and saw the
nest rapidly increase in height; but I regret to add
that he did not remain long enough, fearing he might
create alarm, to witness the interesting act of
replacing the eggs which must have been effected
shortly after; for, upon his return in less than an
hour, he found the hen quietly sitting upon them in
the newly raised nest. In a few days afterwards the
young were hatched, and, as usual, soon quitted the
nest and took to the water with their parents. The
nest was shown to me _in situ_ shortly after, and I
could then plainly discern the formation of the new
with the older part of the fabric.