FEAR IN BIRDS.
The statement that birds instinctively fear man is frequently met with
in zoological works written since the _Origin of Species_ appeared; but
almost the only reason--absolutely the only plausible reason, all the
rest being mere supposition--given in support of such a notion is that
birds in desert islands show at first no fear of man, but afterwards,
finding him a dangerous neighbour, they become wild; and their young
also grow up wild. It is thus assumed that the habit acquired by the
former has become hereditary in the latter--or, at all events, that in
time it becomes hereditary. Instincts, which are few in number in any
species, and practically endure for ever, are not, presumably, acquired
with such extraordinary facility.
Birds become shy where persecuted, and the young, even when not
disturbed, learn a shy habit from the parents, and from other adults
they associate with. I have found small birds shyer in desert places,
where the human form was altogether strange to them, than in
thickly-settled districts. Large birds are actually shyer than the small
ones, although, to the civilized or shooting man they seem astonishingly
tame where they have never been fired at. I have frequently walked quite
openly to within twenty-five or thirty yards of a flock of flamingoes
without alarming them. This, however, was when they were in the water,
or on the opposite side of a stream. Having no experience of guns, they
fancied themselves secure as long as a strip of water separated them
from the approaching object. When standing on dry land they would not
allow so near an approach. Sparrows in England aro very much tamer than
the sparrows I have observed in desert places, where they seldom see a
human being. Nevertheless young sparrows in England are very much tamer
than old birds, as anyone may see for himself. During the past summer,
while living near Kew Gardens, I watched the sparrows a great deal, and
fed forty or fifty of them every day from a back window. The bread and
seed was thrown on to a low roof just outside the window, and I noticed
that the young birds when first able to fly were always brought by the
parents to this feeding place, and that after two or three visits they
would begin to come of their own accord. At such times they would
venture quite close to me, showing as little suspicion as young
chickens. The adults, however, although so much less shy than birds of
other species, were extremely suspicious, snatching up the bread and
flying away; or, if they remained, hopping about in a startled manner,
craning their necks to view me, and making so many gestures and motions,
and little chirps of alarm, that presently the young would become
infected with fear. The lesson was taught them in a surprisingly short
time; their suspicion was seen to increase day by day, and about a week
later they were scarcely to be distinguished, in behaviour from the
adults. It is plain that, with these little birds, fear of man is an
associate feeling, and that, unless it had been taught them, his
presence would trouble them as little as does that of horse, sheep, or
cow. But how about the larger species, used as food, and which have had
a longer and sadder experience of man's destructive power?
The rhea, or South American ostrich, philosophers tell us, is a very
ancient bird on the earth; and from its great size and inability to
escape by flight, and its excellence as food, especially to savages, who
prefer fat rank-flavoured flesh, it must have been systematically
persecuted by man as long as, or longer than, any bird now existing on
the globe. If fear of man ever becomes hereditary in birds, we ought
certainly to find some trace of such an instinct in this species. I have
been unable to detect any, though I have observed scores of young rheas
in captivity, taken before the parent bird had taught them what to fear.
I also once kept a brood myself, captured just after they had hatched
out. With regard to food they were almost, or perhaps quite,
independent, spending most of the time catching flies, grasshoppers, and
other insects with surprising dexterity; but of the dangers encompassing
the young rhea they knew absolutely frothing. They would follow me about
as if they took me for their parent; and, whenever I imitated the loud
snorting or rasping warning-call emitted the old bird in moments of
danger, they would to me in the greatest terror, though no animal was in
sight, and, squatting at my feet, endeavour to conceal themselves by
thrusting their heads and long necks up my trousers. If I had caused a
person to dress in white or yellow clothes for several consecutive days,
and had then uttered the warning cry each time he showed himself to the
birds, I have no doubt that they would soon have acquired a habit of
running in terror from him, even without the warning cry, and that the
fear of a person in white or yellow would have continued all their
lives. Up to within about twenty years ago, rheas were seldom or never
shot in La Plata and Patagonia, but were always hunted on horseback and
caught with the bolas. The sight of a mounted man would set them off at
once, while a person on foot could walk quite openly to within easy
shooting distance of them; yet their fear of a horseman dates only two
hundred years back--a very short time, when we consider that, before the
Indian borrowed the horse from the invader, he must have systematically
pursued the rhea on foot for centuries. The rhea changed its habits when
the hunter changed his, and now, if an _estanciero_ puts down ostrich
hunting on his estate, in a very few years the birds, although wild
birds still, become as fearless and familiar as domestic animals. I have
known old and ill-tempered males to become a perfect nuisance on some
estancias, running after and attacking every person, whether on foot or
on horseback, that ventured near them. An old instinct of a whole race
could not be thus readily lost here and there on isolated estates
wherever a proprietor chose to protect his birds for half a dozen years.
I suppose the Talegallus--the best-known brush-turkey--must be looked on
as an exception to all other birds with regard to the point I am
considering; for this abnormal form buries its eggs in the huge mound
made by the male, and troubles herself no more about them. When the
young is fully developed it simply kicks the coffin to pieces in which
its mother interred it, and, burrowing its way up to the sunshine,
enters on the pleasures and pains of an independent existence from
earliest infancy--that is, if a species born into the world in full
possession of all the wisdom of the ancients, can be said ever to know
infancy. At all events, from Mr. Bartlett's observations on the young
hatched in the Zoological Gardens, it appears that they took no notice
of the old birds, but lived quite independently from the moment they
came out of the ground, even flying up into a tree and roosting
separately at night. I am not sure, however, that these observations are
quite conclusive; for it is certain that captivity plays strange pranks
with the instincts of some species, and it is just possible that in a
state of nature the old birds exercise at first some slight parental
supervision, and, like all other species, have a peculiar cry to warn
the young of the dangers to be avoided. If this is not so, then the
young Talegallus must fly or hide with instinctive tear from every
living thing that approaches it. I, at any rate, find it hard to believe
that it has a knowledge, independent of experience, of the different
habits of man and kangaroo, and dis-criminates at first sight between
animals that are dangerous to it and those that are not. This
interesting point will probably never be determined, as, most unhappily,
the Australians are just now zealously engaged in exterminating their
most wonderful bird for the sake of its miserable flesh; and with less
excuse than the Maories could plead with regard to the moa, since they
cannot deny that they have mutton and rabbit enough to satisfy hunger.
Whether birds fear or have instinctive knowledge of any of their enemies
is a much larger question. Species that run freely on the ground from
the time of quitting the shell know their proper food, and avoid
whatever is injurious. Have all young birds a similarly discriminating
instinct with regard to their enemies? Darwin says, "Fear of any
particular enemy is certainly an instinctive quality, as may be seen in
nestling birds." Here, even man seems to be included among the enemies
feared instinctively; and in another passage he says, "Young chickens
have lost, wholly from habit, that fear of the dog and cat which, no
doubt, was originally instinctive in them." My own observations point to
a contrary conclusion; and I may say that I have had unrivalled
opportunities for studying the habits of young birds.
Animals of all classes, old and young, shrink with instinctive fear from
any strange object approaching them. A piece of newspaper carried
accidentally by the wind is as great an object of terror to an
inexperienced young bird as a buzzard sweeping down with death in its
talons. Among birds not yet able to fly there are, however, some curious
exceptions; thus the young of most owls and pigeons are excited to anger
rather than fear, and, puffing themselves up, snap and strike at an
intruder with their beaks. Other fledglings simply shrink down in the
nest or squat close on the ground, their fear, apparently, being in
proportion to the suddenness with which the strange animal or object
comes on them; but, if the deadliest enemy approaches with slow caution,
as snakes do--and snakes must be very ancient enemies to birds--there is
no fear or suspicion shown, even when the enemy is in full view and
about to strike. This, it will be understood, is when no warning-cry is
uttered by the parent bird. This shrinking, and, in some cases, hiding
from an object corning swiftly towards them, is the "wildness_"_ of
young birds, which, Darwin says again, is greater in wild than in
domestic species. Of the extreme tameness of the young rhea I have
already spoken; I have also observed young tinamous, plovers, coots,
&c., hatched by fowls, and found them as incapable of distinguishing
friend from foe as the young of domestic birds. The only difference
between the young of wild and tame is that the former are, as a rule,
much more sprightly and active. But there are many exceptions; and if
this greater alertness and activity is what is meant by "wildness," then
the young of some wild birds--rhea, crested screamer, &c.--are actually
much tamer than our newly-hatched chickens and ducklings.
To return to what may be seen in nestling birds, n very young, and
before their education has begun, if quietly approached and touched,
they open their bills and take food as readily from a man as from the
parent bird. But if while being thus fed the parent returns and emits
the warning note, they instantly cease their hunger-cries, close their
gaping mouths, and crouch down frightened in the nest. This fear caused
by the parent bird's warning note begins to manifest itself even before
the young are hatched--and my observations on this point refer to
several species in three widely separated orders. When the little
prisoner is hammering at its shell, and uttering its feeble _peep,_ as
if begging to be let out, if the warning note is uttered, even at a
considerable distance, the strokes and complaining instantly cease, and
the chick will then remain quiescent in the shell for a long time, or
until the parent, by a changed note, conveys to it an intimation that
the danger is over. Another proof that the nestling has absolutely no
instinctive knowledge of particular enemies, but is taught to fear them
by the parents, is to be found in the striking contrast between the
habits of parasitical and genuine young in the nest, and after they have
left it, while still unable to find their own food. I have had no
opportunities of observing the habits of the young cuckoo in England
with regard to this point, and do not know whether other observers have
paid any attention to the matter or not, but I am very familiar with the
manners of the parasitical starling or cow-bird of South America. The
warning cries of the foster parent have no effect on the young cow-bird
at any time. Until they are able to fly they will readily devour worms
from the hand of a man, even when the old birds are hovering close by
and screaming their danger notes, and while their own young, if the
parasite has allowed any to survive in the nest, are crouching down in
the greatest fear. After the cow-bird has left the nest it is still
stupidly tame, and more than once I have seen one carried off from its
elevated perch by a milvago hawk, when, if it had understood the warning
cry of the foster parent, it would have dropped down into the bush or
grass and escaped. But as soon as the young cow-birds are able to shift
for themselves, and begin to associate with their own kind, their habits
change, and they become suspicious and wild like other birds.
On this point--the later period at which the parasitical young bird
acquires fear of man--and also bearing on the whole subject under
discussion, I shall add here some observations I once made on a dove
hatched and reared by a pigeon at my home on the pampas. A very large
ombú tree grew not far from the dove-cote, and some of the pigeons used
to make their nests on the lower horizontal branches. One summer a dove
of the most common species, Zenaida maculata, in size a third less than
the domestic pigeon, chanced to drop an egg in one of these nests, and a
young dove was hatched and reared; and, in due time, when able to fly,
it was brought to the dove-cote. I watched it a great deal, and it was
evident that this foster-young, though' with the pigeons, was not nor
ever would be of them, for it could not take kiudly to their flippant
flirty ways. Whenever a male approached it, and with guttural noises and
strange gestures made a pompous declaration of amorous feelings, the
dove would strike vigorously at its undesirable lover, and drive him
off, big as he was; and, as a rule, it would sit apart, afoot or so,
from the others. The dove was also a male; but its male companions, with
instinct tainted by domestication, were ignorant alike of its sex and
different species. Now, it chanced that my pigeons, never being fed and
always finding their own living on the plain like wild birds, were,
although still domestic, not nearly so tame as pigeons usually are in
England. They would not allow a person to approach within two or three
yards of them without flying, and if grain was thrown to them they would
come to it very suspiciously, or not at all. And, of course, the young
pigeons always acquired the exact degree of suspicion shown by the
adults as soon as they were able to fly and consort with the others. But
the foundling Zenaida did not know what their startled gestures and
notes of fear meant when a person approached too near, and as he saw
none of his own kind, he did not acquire their suspicious habit. On the
contrary, he was perfectly tame, although by parentage a wild bird, and
showed no more fear of a man than of a horse. Throughout the winter it
remained with the pigeons, going afield every day with them, and
returning to the dove-cote; but as spring approached the slight tie
which united him to them began to be loosened; their company grew less
and less congenial, and he began to lead a solitary life. But he did not
go to the trees yet. He came to the house, and his favourite perch was
on the low overhanging roof of a vine-covered porch, just over the main
entrance. Here he would pass several hours every day, taking no notice
of the people passing in and out at all times; and when the weather grew
warm he would swell out his breast and coo mournfully by the hour for
our pleasure.
We can, no doubt, learn best by observing the behaviour of nestlings and
young birds; nevertheless, I find much even in the confirmed habits of
adults to strengthen me in the belief that fear of particular enemies is
in nearly all cases--for I will not say all--the result of experience
and tradition.
Hawks are the most open, violent, and persistent enemies birds have; and
it is really wonderful to see how well the persecuted kinds appear to
know the power for mischief possessed by different raptorial species,
and how exactly the amount of alarm exhibited is in proportion to the
extent of the danger to be apprehended. Some raptors never attack birds,
others only occasionally; still others prey only on the young and
feeble; and, speaking of La Plata district, where I have observed hawks,
from the milvago chimango--chiefly a carrion-eater--to the destructive
peregrine falcon, there is a very great variety of predatory habits, and
all degrees of courage to be found; yet all these raptors are treated
differently by species liable to be preyed on, and have just as much
respect paid them as their strength and daring entitles them to, and no
more, So much discrimination must seem almost incredible to those who
are not very familiar with the manners of wild birds; I do not think it
could exist if the fear shown resulted from instinct or inherited habit.
There would be no end to the blunders of such an instinct as that; and
in regions where hawks are extremely abundant most of the birds would be
in a constant state of trepidation. On the pampas the appearance of the
comparatively harmless chimango excites not the least alarm among small
birds, yet at a distance it closely resembles a henharrier, and it also
readily attacks young, sick, and wounded birds; all others know how
little they have to fear from it. When it appears unexpectedly,
sweeping over a hedge or grove with a rapid flight, it is sometimes
mistaken for a more dangerous species; there is then a little flutter of
alarm, some birds springing into the air, but in two or three seconds of
time they discover their mistake, and settle down quietly again, taking
no further notice of the despised carrion-eater. On the other hand, I
have frequently mistaken a harrier (Circus cinereus, in the brown state
of plumage) for a chimango, and have only discovered my mistake by
seeing the commotion among the small birds. The harrier I have
mentioned, also the C. macropterus, feed partly on small birds, which
they flush from the ground and strike down with their claws. When the
harrier appears moving along with a loitering flight near the surface,
it is everywhere attended by a little whirlwind of alarm, small birds
screaming or chirping excitedly and diving into the grass or bushes; but
the alarm does not spread far, and subsides as soon as the hawk has
passed on its way. Buzzards (Buteo and Urubitinga) are much more feared,
and create a more widespread alarm, and they ars certainly more
destructive to birds than harriers. Another curious instance is that of
the sociable hawk (Rostrhanrus sociabilis). This bird spends the summer
and breeds in marshes in La Plata, and birds pay no attention to it, for
it feeds exclusively on water-snails (Ampullaria). But when it visits
woods and plantations to roost, during migration, its appearance creates
as much alarm as that of a true buzzard, which it closely resembles.
Wood-birds, unaccustomed to see it, do not know its peculiar preying
habits, and how little they need fear its presence. I may also mention
that the birds of La Plata seem to fear the kite-like Elanus less than
other hawks, and I believe that its singular resemblance to the common
gull of the district in its size, snowy-white plumage and manner of
flight, has a deceptive effect on most species, and makes them so little
suspicious of it.
The wide-ranging peregrine falcon is a common species in La Plata,
although, oddly enough, not included in any notice of the avifauna of
that region before 1888. The consternation caused among birds by its
appearance is vastly greater than that produced by any of the raptors I
have mentioned: and it is unquestionably very much more destructive to
birds, since it preys exclusively on them, and, as a rule, merely picks
the flesh from the head and neck, and leaves the untouched body to its
jackal, the carrion-hawk. When the peregrine appears speeding through
the air in a straight line at a great height, the feathered world, as
far as one able to see, is thrown into the greatest commo-tion, all
birds, from the smallest up to species large as duck, ibis, and curlew,
rushing about in the air as if distracted. When the falcon has
disappeared in the sky, and the wave of terror attending its progress
subsides behind it, the birds still continue wild and excited for some
time, showing how deeply they have been moved; for, as a rule, fear is
exceedingly transitory in its effects on animals.
I must, before concluding this part of my subject, mention another
raptor, also a true falcon, but differing from the peregrine in being
exclusively a marsh-hawk. In size it is nearly a third less than the
male peregrine, which it resembles in its sharp wings and manner of
flight, but its flight is much more rapid. The whole plumage, is
uniformly of a dark grey colour. Unfortunately, though I have observed
it not fewer than a hundred times, I have never been able to procure a
specimen, nor do I find that it is like any American falcon already
described; so that for the present it must remain nameless. Judging
solely from the effect produced by the appearance of this hawk, it must
be even more daring and destructive than its larger relation, the
peregrine. It flies at a great height, and sometimes descends vertically
and with extraordinary velocity, the wings producing a sound like a
deep-toned horn. The sound is doubtless produced at will, and is
certainly less advantageous to the hawk than to the birds it pursues. No
doubt it can afford to despise the wing-power of its quarry; and I have
sometimes thought that it takes a tyrannous delight in witnessing the
consternation caused by its hollow trumpeting sound. This may be only a
fancy, but some hawks do certainly take pleasure in pursuing and
striking birds when not seeking prey. The peregrine has been observed,
Baird says, capturing birds, only to kill and drop them. Many of the
Felidae, we know, evince a similar habit; only these prolong their
pleasure by practising a more refined and deliberate cruelty.
The sudden appearance overhead of this hawk produces an effect wonderful
to witness. I have frequently seen all the inhabitants of a marsh struck
with panic, acting as if demented, and suddenly grown careless to all
other dangers; and on such occasions I have looked up confident of
seeing the sharp-winged death, suspended above them in the sky. All
birds that happen to be on the wing drop down as if shot into the reeds
or water; ducks away from the margin stretch out their necks
horizontally and drag their bodies, as if wounded, into closer cover;
not one bird is found bold enough to rise up and wheel about the
marauder--a usual proceeding in the case of other hawks; while, at every
sudden stoop the falcon makes, threatening to dash down on his prey, a
low cry of terror rises from the birds beneath; a sound expressive of an
emotion so contagious that it quickly runs like a murmur all over the
marsh, as if a gust of wind had swept moaning through, the rushes. As
long as the falcon hangs overhead, always at a height of about forty
yards, threatening at intervals to dash down, this murmuring sound, made
up of many hundreds of individual cries, is heard swelling and dying
away, and occasionally, when he drops lower than usual, rising to a
sharp scream of terror.
Sometimes when I have been riding over marshy ground, one of these hawks
has placed himself directly over my head, within fifteen or twenty yards
of me; and it has perhaps acquired the habit of following a horseman in
this way in order to strike at any birds driven up. On one occasion my
horse almost trod on a couple of snipe squatting terrified in the short
grass. The instant they rose the hawk struck at one, the end of his wing
violently smiting my cheek as he stooped, and striking at the snipe on a
level with the knees of my horse. The snipe escaped by diving under the
bridle, and immediately dropped down on the other side of me, and the
hawk, rising up, flew away.
To return. I think I am justified in believing that fear of hawks, like
fear of men, is, in very nearly all cases, the result of experience and
tradition. Nevertheless, I think it probable that in some species which
have always lived in the open, continually exposed to attack, and which
are preferred as food by raptors, such as duck, snipe, and plover, the
fear of the falcon may be an inherited habit. Among passerine birds I am
also inclined to think that swallows show inherited fear of hawks.
Swallows and humming-birds have least to fear from raptors; yet, while
humming-birds readily pursue and tease hawks, thinking as little of them
as of pigeons or herons, swallows everywhere manifest the greatest
terror at the approach of a true falcon; and they also fear other birds
of prey, though in a much less degree. It has been said that the
European hobby occasionally catches swal-lows on the wing, but this
seems a rare and exceptional habit, and in South America I have never
seen any bird of prey attempt the pursuit of a swallow. The question
then arises, how did this unnecessary fear, so universal in swallows,
originate? Can it be a survival of a far past--a time when some
wide-ranging small falcon, aerial in habits as the swallow itself,
preyed by preference on hirundines only?
[NOTE.-Herbert Spencer, who accepts Darwin's inference, explains how the
fear of man, acquired by experience, becomes instinctive in birds, in
the following passage: "It is well known that in newly-discovered lands
not inhabited by man, birds are so devoid of fear as to allow themselves
to be knocked over with sticks; but that, in the course of generations,
they acquire such a dread of man as to fly on his approach: and that
this dread is manifested by young as well as by old. Now unless this
change be ascribed to the killing-off of the least fearful, and the
preservation and multiplication of the most fearful which, considering
the comparatively small number killed by man, is an inadequate cause, it
must be ascribed to accumulated experience; and each experience must be
held to have a share in producing it. We must conclude that in each bird
that escapes with injuries inflicted by man, or is alarmed by the
outcries of other members of the flock (gregarious creatures of any
intelligence being necessarily more or less sympathetic), there is
established an association of ideas between the human aspect and the
pains, direct and in-direct, suffered from human agency. And we must
further con-clude, that the state of consciousness which compels the
bird to take flight, is at first nothing more than an ideal reproduction
of those painful impressions which before followed man's approach; that
such ideal reproduction becomes more vivid and more massive as the
painful experiences, direct or sympathetic, increase; and that thus the
emotion, in its incipient state, is nothing else than an aggregation of
the revived pains before experience.
"As, in the course of generations, the young birds of this race begin to
display a fear of man before yet they have been injured by him, it is an
unavoidable inference that the nervous system of the race has been
organically modified by these experiences, we have no choice but to
conclude, that when a young bird is led to fly, it is because the
impression produced in its senses by the approaching man entails,
through an incipiently reflex action, a partial excitement of all those
nerves which in its ancestors had been excited under the like
conditions; that this partial excitement has its accompanying painful
consciousness, and that the vague painful consciousness thus arising
constitutes emotion proper--_emotion undecomposable into specific
experiences, and, therefore, seemingly homogeneous"_ (Essays, vol. i. p.
320.)]
It is comforting to know that the "unavoidable inference" is, after all,
erroneous, and that the nervous system in birds has not yet been
organically altered as a result of man's persecution; for in that case
it would take long to undo the mischief, and we should be indeed far
from that "better friendship" with the children of the air which many of
us would like to see.