One bird there is to whom these scattered fir plantations, with their
surrounding, sandy territory, dotted here and there with a gaunt
elder-bush or gnarled old hawthorn, are extremely dear, and that
bird is the nightjar. Nightjars are very common here. If spruces and
larches alternate with the prevailing Scotch fir, they love to sit on
the extreme tip-top of one of these, and there, sometimes, they will
“churr” without intermission for an extraordinary length of time.
Sometimes it seems as if the bird would never either move, or leave
off, but all at once, with a suddenness which surprises one, it rises
into the air, and goes off with several loud claps of the wings above
the back, and uttering another note--“quaw-ee, quaw-ee”--which is never
heard, save during flight. After a few circles it may be joined by
a companion--probably its mate--upon which, as in an excess of glad
excitement, it will clap its wings, again, a dozen or score of times
in succession. The two then pursue one another, wheeling in swiftest
circles and making, often, the most astonishing turns and twists, as
they strive either to escape or overtake. Often they will be joined
by a third or fourth bird, and more fast, more furious, then, becomes
the airy play. No words can give an idea of the extreme beauty of
the flight of these birds. In their soft moods they seem to swoon on
the air, and, again, they flout, coquette, and play all manner of
tricks with it. Grace and jerkiness are qualities quite opposite to
each other. The nightjar, when “i’ the vein,” combines them with easy
mastery, and to see this is almost to have a new sensation. It is as
though Shakespeare’s Ariel were to dance in a pantomime,[3] yet still
be Shakespeare’s Ariel. As one watches such beings in the deepening
gloom, they seem not to be real, but parts of the night’s pageant
only--dusky imaginings, shadows in the shapes of birds. What glorious
powers of motion! One cannot see them without wishing to be one of them.
I have spoken of the nightjar clapping its wings a dozen or score of
times in succession. This is not exaggerated. I have counted up to
twenty-five claps myself, and this was less than the real number, as
the first tumultuous burst of them was well-nigh over before I began to
count. It is not easy, indeed, to keep up with the bird, and when it
stops, one is, generally, a little behind. The claps are wonderfully
loud and distinct--musical they always sound to me--and I believe,
myself, that they are almost as sexual in their character as is the
bleating of the snipe. The habit has, indeed, become now so thoroughly
ingrained that any sudden emotion, as, say, surprise or fear, is apt to
call it forth, of which principle, in nature, many illustrations might
be given; but it is when two or more birds are sporting together--or
when one, after a long bout of “churring,” springs from the tree, and,
especially, in a swift, downward flight to the ground, where its mate
is probably reclining--that one hears it in its perfection. Why so
little has been said about this very marked and noticeable peculiarity,
why a work of high authority should only tell us that “in general
its flight is silent, but at times, when disturbed from its repose,
its wings may be heard to smite together,” I really do not know. The
expression used suggests that the sound made by the smiting of the
wings is but slight, whereas one would have to be fairly deaf not to
hear it. And why only “when disturbed”? Under such circumstances the
performance will always be a poor one, but it is not by startling the
bird, but by waiting, unseen and silent, that one is likely to hear it
in its perfection, and then not alarm or disquietude, but joy will have
produced it--it is a glad ebullition.
The domestic habits of the nightjar are very pretty and interesting.
No bird can be more exemplary in its conjugal relations, and in its
care and charge of the young. Both husband and wife take part in the
incubation of the eggs, and there is, perhaps, no prettier sight than
to see the one relieve the other upon them. It is the female bird, as I
believe, that sits during the day--which, to her, is as the night--and,
shortly after the first churring round about begins to be heard,
her partner may be seen flying up from some neighbouring clump of
trees, and, as he comes, uttering, at intervals, that curious note of
“quaw-ee, quaw-ee,” which seems to be the chief aerial vehicle of the
domestic emotions. As it comes nearer, it is evidently recognised by
the sitting bird, who churrs in response, but so softly that human ears
can only just catch the sound. The male now settles beside her, churrs
softly himself, and then pressing and, as it were, snoozling against
her, seems to insist that it is now his turn. For a few seconds the
pair sit thus, churring together, and, whilst doing so, both wag their
tails--and not only their tails, but their whole bodies also--from
side to side, like a dog in a transport of pleasure. Then all at once,
without any fondling or touching with the beak--which, indeed, I have
never seen in them--the female darts away, leaving the male upon the
eggs. She goes off instantaneously, launching, light as a feather,
direct from her sitting attitude, without rising, or even moving,
first. In other cases the cock bird settles himself a little farther
away, and the hen at once flies off. There are infinite variations in
the pretty scene, but the prettiest, because the most affectionate, is
that which I have described, where the male, softly and imperceptibly,
seems to squeeze himself on to the eggs, and his partner off them. I
have seen tame doves of mine act in just the same way, and here, too,
both would coo together upon the nest.
In regard to the two sexes churring, thus, in unison, I can assert,
in the most uncompromising manner, that they do so, having been
several times a witness of it, at but a few steps’ distance, and in
broad daylight, I may almost say, taking the time of the year into
consideration. The eyes, indeed, are as important as the ears in coming
to a conclusion on the matter, for not only is the tail wagged in these
little duets, but with the first breath of the sound, the feathers of
the bird’s throat begin to twitch and vibrate, in a very noticeable
manner. Various authorities, it is true, either state or imply that
the male nightjar alone churrs, or burrs, or plays the castanets,
however one may try to describe that wonderful sound, which seems to
become the air itself, on summer evenings, anywhere where nightjars
are numerous. But these authorities are all mistaken, and as soon as
they take to watching a pair of the birds hatching their eggs, they
will find that they were, but not before, for there is no other way
of making certain. It is true that the churr thus uttered, though as
distinct as an air played on the piano, is now extraordinarily subdued,
of so soft and low a quality that, remembering what it more commonly
is, one feels inclined to marvel at such a power of modulation. But it
is just the same sound “in little”--how, indeed, can such a sound be
mistaken?--and, after all, since a drum can be beaten lightly, there is
no reason why an instrument, which is part of the performer itself,
should be less under control. What is really interesting and curious
is to hear such a note expressing, even to one’s human ears, the soft
language of affection--for it does do so in the most unmistakable
manner.
Though, as we have seen, both the male and female nightjar help in the
hatching of the eggs, the female takes the greater part of it upon
herself, and is also much more _au fait_ in the business--I believe
so, at least. The sexes are, indeed, hard to distinguish, and, as the
light fades, it becomes, of course, impossible to do so. Still, one
cannot watch a sitting pair, evening after evening, for an hour or more
at a time, without forming an opinion on such a point; and this is
mine. We may assume, perhaps, that it is the female bird who sits all
day, without once being relieved. If so, it is the male who flies up
in the evening, and from this point one can judge by reckoning up the
changes, and timing each bird on the eggs. This I did, and it appeared
to me, not only that the hen was, from the first, the most assiduous
of the two, but, also, that the cock became less and less inclined to
attend to the eggs, as the time of their hatching drew near. So, too,
he seemed to me to sit upon them with less ease and to have a tendency
to get them separated from each other, which, in one case, led to a
scene which, to me, seemed very interesting, as bearing on the bird’s
intelligence, and which I will therefore describe. I must say that,
previously to this, when both birds were away, I had left my shelter
in order to pluck an intervening nettle or two, and thus get a still
clearer view, and I had then noticed that the two eggs lay rather
wide apart. Shortly afterwards one of the birds, which I judged to be
the male, returned, and in getting on to the eggs--which it did by
pushing itself along the ground--it must, I think, have moved them
still farther from one another. At any rate it became necessary, in
the bird’s opinion, to alter their relative position, and in order to
do this it went into a very peculiar attitude. It, as it were, stood
upon its breast, with its tail raised, almost perpendicularly, into
the air, so that it looked something like a peg-top set, peg upwards,
on the broad end, the legs being, at no time, visible. Thus poised, it
pressed with the under part of its broad beak--or, as one may say, with
its chin--first one egg and then the other against its breast, and, so
holding it, moved backwards and forwards over the ground, presenting a
strange and most unbirdlike appearance. The ground, however, was not
even, and despite the bird’s efforts to get the two eggs together,
one of them--as I plainly saw--rolled down a little declivity. At the
bottom some large pieces of fir-bark lay partially buried in the sand,
and under one of these the egg became wedged. The bird was unable to
get it out, so as to bring it up the hill again to where the other egg
lay, for the bark, by presenting an edge, prevented it from getting
its chin against the farther side of the one that was fast, so as to
press it against its breast as before--though making the most desperate
efforts to do so. Wedging its head between the bark and the ground, it
now stood still more perpendicularly upright on its breast, and, in
this position, shoved and shouldered away, most desperately. After
each effort it would lie a little, as if exhausted, then waddle to
the other egg, and settle itself upon it; then, in a minute or two,
return to the one it had left, and repeat its efforts to extricate it.
At last, however, after nearly half-an-hour’s labour, an idea seemed
to occur to it. It went again to the properly-placed egg, but instead
of settling down upon it, as before, began to move it to the other
one, in the way that I have described. “If the mountain will not go to
Mahomet, Mahomet must go to the mountain”--that was clearly the process
of reasoning, and seeing how set the bird’s mind had been on one course
of action--how it had toiled and struggled and returned to its efforts,
again and again--its subsequent, sudden adoption of another plan
showed, I think, both intelligence and versatility. It, in fact, acted
just as a sensible man would have done. It tried to do the best thing,
till convinced it was impossible, and then did the second best. Having
thus got the two eggs together again, it tried hard to push away the
piece of bark--which was half buried in the sand--backwards, with its
wings, feet, and tail, after the manner in which the young cuckoo--in
spite of the anti-vaccinationists[4]--ejects its foster brothers and
sisters from the nest. Finally, as it grew dark, it flew away. I then
went out to look, and found that the bird had been successful in its
efforts, to a certain extent. The two eggs now lay together, and
though not quite on the same level, and though the piece of bark was
still in the way of one of them, both might yet have been covered,
though not with ease, and so, possibly, hatched out. However, had I
left them as they were, I have no doubt that, assisted, perhaps, by its
partner, the bird would have continued to work away till matters were
quite satisfactory. But having seen so much, and since it would soon
have been too dark to see anything more, I thought I would interfere,
for once, and so removed the bark, and smoothing down the declivity,
laid the eggs side by side, on a flat surface. I must add that whilst
this nightjar was thus struggling to extricate its eggs, it uttered
from time to time a low querulous note.
When the eggs are hatched, both parents assist in feeding the chicks,
and the first thing that one notices--and to me, at least, it was
an interesting discovery--is that they feed them, not by bringing
them moths or cockchafers--on which insects the nightjar is supposed
principally to feed--in their bill, but by a process of regurgitation,
after the manner of pigeons. There is one difference, however, viz.,
that whereas the bill of the young pigeon is placed within that of the
parent, the young nightjar seizes the parent’s bill in its own. Those
peculiar jerking and straining motions, which are employed to bring
up the food--from the crop, as I suppose--into the mouth, are the
same, or, at least, closely similar, in either case. I have watched
the thing taking place so often, and from so near, that I cannot, I
think, have been mistaken. There was, usually, a good light, when the
first ministrations began, and even after it had grown dark I could
almost always see the outline of the bird’s head and beak, defined
against the sky, as it sat perched upon the bare, thin point of an
elder-stump, from which it generally flew to feed the chicks. Never
was this outline broken by any projection, as it must have been had an
insect of any size been held in the bill. A more conclusive argument
is, I think, that the chicks were generally fed, in the way I have
described, several times in succession. They would always come out
from under their mother, as the evening approached, and, jumping up
at her bill, try to insist on her feeding them. Whether she ever fed
them, then, before leaving the nest, I cannot, for certain, say. I
do not think she did, nor can I see how she could have had anything
in her crop after sitting, fasting, all day. As a rule, at any rate,
she first flew off, and fed them only on her return. When she flew,
I used to watch her for as long as I could, and would sometimes see
her, as well as the other one, circling and twisting about in the air,
in pursuit of insects, as it appeared to me. I never saw any insects,
however, as I should have done had they been of any size, nor did I
ever see anything, on the part of the birds, that looked like a snatch
in the air with open bill. But if insects were being caught at all,
the bill must, of course, have been opened to some extent, and this
shows, I think--for what else could the birds have been doing?--that
it is very difficult in the dusk of evening to see it opened, even
when it is. For my own part, I have found it difficult--not to say
impossible--to see swallows open their beaks, even in broad daylight,
when they were obviously hawking for insects. The point is an important
one, I think, in considering what kinds of insects the nightjar more
habitually feeds on, and how, in general, it procures them--questions
which, having been settled, as it seems to me, merely by assertion,
are entirely reopened by the fact that the young are fed in the way I
have described. For if moths and cockchafers are the bird’s principal
food, why should it not bring these to the young, in the ordinary way?
But if it swallows huge quantities of insects, so small that it cannot
seize them in the bill, but must engulf them, merely, as it flies, as
a whale does infusoria, we can then see a reason for its not doing
so. How else, but by disgorging it in the form of a pulp, could such
food as this be given to the chick? and if to do so became the bird’s
habitual practice, it would not be likely to vary it in any instance.
Now the green woodpecker feeds largely on ants, and, further on, I will
give my reasons for believing that it feeds its young by regurgitation.
The little woodpecker, however, I have watched coming, time and time
again, to its hole in the tree-trunk, with its bill full of insects of
various kinds, and of a respectable size, so that there is no doubt
that it gives these to its brood, as does a thrush or a blackbird. What
can make a difference, in this respect, between two such closely-allied
species, if it be not that the one has taken to eating ants, minute
creatures which it has to swallow wholesale, and could not well carry
in the bill? When, therefore, we find the parent nightjar regurgitating
food into the chick’s mouth, we may suspect that it also swallows
large quantities of insects of an equally small, or smaller size. The
beak need neither be widely nor continuously opened, for many such to
be engulfed as the bird sailed through a strata of them; but even if
it were both, we need not wonder at its not often being remarked, in a
species which flies and feeds, mostly, by night, when it is both dark,
and people are in bed. Still, I find in Seebohm’s “History of British
Birds” the following: “The bird has been said to hunt for its food,
with its large mouth wide open, but this is certainly an error.” The
first part of the sentence impresses me more than the last. Why _has_
the bird its tremendous, bristle-fringed gape? Does it not suggest a
whale’s mouth, with the baleen? Other birds catch individual insects as
cleverly, without it.
There is another consideration which makes me think that nightjars feed
much in this way. They hardly begin to fly about, before 8.30 in the
evening, and between 3 and 4, next morning, they have retired for the
day. Now I have watched them closely, on many successive evenings in
June and July, and, for the life of me, I could never make out what
food they were getting, or, indeed, that they were getting any, up to
at least 10 o’clock. For much of the time they would be sitting on a
bough, or perched on a fir-top, and churring, and, when they flew, it
was often straight to the ground, and then back, again, to the same
tree. They certainly did not seem to be catching insects when they
did this, and their longer flights were not, as a rule, round trees,
and often resolved themselves into chasing and sporting with one
another. That they occasionally caught moths or cockchafers seems, in
itself, likely, but I never had reason to suppose that these were their
particular quarry. It seems strange that I should have so rarely seen
them catch any large insect--I cannot, indeed, remember an instance;
but, on the other hand, they might well have engulfed crowds of small
ones, as they flew, without my being able to detect it, and without any
special effort to do so. That the air is often full of these--gnats,
little flies, &c.--may be conjectured by watching swallows, and also
bats. Indeed, one may both see and feel them oneself--in cycling, for
instance, when I have often had a small beetle, constructed on the
general plan of a devil’s coach-horse, sticking all over me. For all
the above reasons, my view is that it is the smaller things of the air
which form the staple of the nightjar’s food, and that its huge gape,
and, possibly, the bristles on either side of the upper jaw, stand in
relation to the enormous numbers of these which it engulfs. The bird,
in fact--and this would apply equally to the other members of the
family--plays, in my idea, the part of an aerial whale.
I have watched a pair of nightjars through the whole process of
hatching out their eggs and bringing up their young, as long as the
latter were to be found; for they got away from the nest--if the
bare ground may be called one--long before they could fly. It was
on the last day of June that the chicks first burst upon me. I had
been watching the sitting bird for some time, and had noticed that
the feathers just under her chin were quivering, while her beak was
held slightly--as slightly as possible--open. I thought she must be
churring, but no sound reached my ear, so I concluded she was asleep
merely, and dreaming that she was. She sat so still and close that I
never imagined she could have ceased incubating. I had seen her eggs,
too, as I thought, yesterday; but in this I may have been mistaken. All
at once, however, a strange little, flat, fluffy thing ran out from
under her breast, and, stretching up, touched its mother’s beak with
its own. She did not respond, however, on which the chick ran back,
disappointed. As soon as that queer little figure had disappeared, I
was all eagerness to see it again, but hour after hour went by, the
old bird drowsed and dreamed, and still there was no re-emergence. It
seemed as though I had had an hallucination of the senses, all looked
so still and unchangeable; but, at last, as the evening began to fall,
and churring to be heard round about, out, suddenly, came the little
apparition again, accompanied, this time, with an exact duplicate of
itself. The two appeared from opposite sides, and, with a simultaneous
jump, seized and struggled for the beak of the mother, who again
resisted, and then, suddenly, darted off, just as, with “quaw-ee,
quaw-ee,” the partner bird flew up. He settled himself beside the
chicks, and when they sprang up at him, as they had just before done
at the mother, he fed one thoroughly, but not the other, flying off
immediately afterwards. The hen soon returned, and fed both the chicks
several times, always, as I say, by the regurgitatory process. Between
the intervals of feeding them, she kept uttering a little croodling
note, expressive of quiet content and affection, whilst the chicks,
more rarely, gave vent to a slender pipe. One of them I now[5] saw to
be a little larger than the other, and of a lighter colour, and this
bird seemed always to be the more greedy. The difference, in all three
respects, increased from day to day, till at last, in regard to size,
it became quite remarkable. The two parent birds were much alike in
this respect, and as the two chicks had been born within a day of each
other, it seems odd that there should have been this disparity between
them. But so it was.
It appeared to me that, as the big chick was certainly the greedier
of the two, so both the parents tried to avoid the undue favouring of
it at the expense of the other. If so, however, their efforts were
not very effective. It was difficult, indeed, to avoid the eagerness
of whichever one first jumped up at them. As they got older, the
chicks were left more and more alone in the nest, or, rather, on
the spot where they were born. At first, they used to lie there in
a wonderfully quiescent way, not moving, sometimes, for hours at a
time, but gradually they became more active, and would make little
excursions, from which they did not always trouble to return. Thus,
by degrees, the old nesting-site became lost, for the parents, though
for some time they continued to show an affection for it, settled
more and more by the chicks, or, if they did not see them, somewhere
near about, and then called them up to them. This they did with the
little croodling note which I have spoken of, and which the chicks, on
hearing, would answer with a “quirr, quirr,” and run towards it, then
stop to listen, and run again, getting, all the while, more and more
excited. If the old bird was at any distance, which, as the chicks got
older, was more and more frequently the case, there would sometimes
be long intervals between these summoning notes--if we assume them
to be such--and, during these, the chicks lay still and, generally,
close together, as if they were in the nest. When I walked to them, on
these occasions, both the parent birds would start up from somewhere
in the neighbourhood, and whilst one of them flew excitedly about, the
other--which I took to be the hen--used always to spin, in the most
extraordinary manner, over the ground, looking more like an insect
than a bird, or, at any rate, suggesting, by her movements, those of a
bluebottle that has got its wings scorched in the gas, and fallen down
on the table. Whilst she was doing this, the chicks would, sometimes,
run away, but, quite as often, one or both of them would remain where
they were--apparently quite unconcerned--and allow me to take them up.
When, at last, the mother followed the example of her mate, and flew
off, she showed the same superior degree of anxiety in the air, as
she had, before, upon the ground. She would come quite near me, hover
about, dart away and then back again, sit on a thistle-tuft, leave it,
as though in despair, and, at last, re-alight on the ground, where she
kept up a loud, distressed kind of clucking, which, at times, became
shriller, rising, as it were, to an agony. The male was a little less
moved. Still, he would fly quite near, and often clap his wings above
his back. I cannot, now, quite remember whether the male ever began by
spinning over the ground, in the same way as the hen, but, if he did,
it did not last long, and he soon took to flight.
It will be seen from the above that the chicks are very well able to
get about. They run, indeed, as easily, if not quite so fast, as a
young duckling, and this power is retained by the grown bird, in spite
of its aerial habits, for I have seen my two pursuing one another over
the ground with perfect ease and some speed, seeming, thus, to run
without legs, for these were at no time visible. The ground-breeding
habits of the nightjar probably point to a time when it was, much more,
a ground-dwelling bird, and as these habits have continued, we can
understand a fair power of locomotion having been retained also. My own
idea is that the nuptial rite is, sometimes at least, performed on the
ground, but of this I have had no more than an indication.[6]
The nightjar utters many notes, besides that very extraordinary one by
which it is so well known, and which has procured for it many of its
names. I have made out at least nineteen others; but I do not believe
that any very special significance belongs to the greater number of
them, and I hold the same view in regard to many other notes uttered by
various birds, which are supposed, always, to have some well-defined,
limited meaning. Each, no doubt, has a meaning, at the time it is
uttered, but I think it is, generally, one of many possible ones which
may all be expressed by the same note, such note being the outcome, not
of a definite idea, but of a certain state of feeling. Surprise, for
instance, may be either a glad surprise or a fearful surprise, and very
varied acts spring from either joy or fear. With ourselves definite
ideas have become greatly developed; but animals may live, rather, in
a world of emotions, which would then be much more a cause of their
actions, and, consequently, of the cries which accompanied them, than
the various ideas appertaining to each. Because, for instance, a rabbit
stamps with its hind feet when alarmed, and other rabbits profit by
its doing so, why need this be done as a signal, which would involve a
conscious design? Is it not more likely that the stamp is merely the
reaction to some sudden, strong emotion, which need not always be that
of fear? If rabbits stamp, sometimes, in sport and frolic--as I think
they do--this cannot be a signal, and therefore we ought not to assume
that it is, when it has the appearance, or produces the effect, of
one. All we can say, as it seems to me, is that excitement produces a
certain muscular movement, which, according to the class of excitement
to which it belongs, may mean or express either one thing or another.
Such a movement, or such a cry, is like the bang of a gun, which may
have been fired either as a salute or with deadly intent. However, if
the nightjar’s nineteen notes really express nineteen definite ideas
in the bird’s mind, I can only confess that I have not discovered what
these are. Some of the sounds, indeed, are very good illustrations
of the view here brought forward--for instance, the croodling one
just mentioned, which, when it calls the chicks from a distance,
seems as though it could have no other meaning than this, but which
may also be heard when parent and young are sitting together, and,
again, between the intervals in the process of feeding the latter. Is
it not, therefore, a sound belonging to the soft, parental emotions,
from which sometimes one class of actions, and sometimes another, may
spring--the note being the same in all? From the number of sounds which
the nightjar has at command, I deduce that it is a bird of considerable
range and variety of feeling, which would be likely to make it an
intelligent bird also; and this, in my experience, it is. Two of the
most interesting notes, or rather series of notes, which it utters,
are modifications, or extensions, of the only one which has received
much attention--the churr, namely. One of these is a sort of jubilee
of gurgling sounds, impossible to describe, at the end of it; and the
other--much rarer--a beatification, so to speak, of the churr itself,
also towards the end, the sound becoming more vocal and expressive,
and losing the hard, woodeny, insect-like character which it usually
has. To these I will not add a mere list of sounds, as to the import
of which--not wishing to say more than I know--I have nothing very
particular to say.
These are days in which the theory of protective coloration has
been run--especially, in my opinion, in the case of the higher
animals--almost to death. It may not be amiss, therefore, that I
should mention the extraordinary resemblance which the nightjar
bears to a piece of fir-bark, when it happens to be sitting amidst
pieces of fir-bark, and not amidst other things, which, when it is,
it no doubt resembles as strongly. If, at a short distance, and for a
considerable time, one steadily mistakes one thing for another thing,
with the appearance of which one is well acquainted, this, I suppose,
is fair proof of a likeness, provided one’s sight is good. Such a
mistake I have made several times, and especially upon one occasion.
It was midday in June, and a sunny day as well. I had left the bird in
question, for a little while, to watch another, and when I returned,
it was sitting in the same place, which I knew like my study table. My
eye rested full upon it, as it sat, but not catching the outline of
the tip of the wings and tail, across a certain dry stalk, as I was
accustomed to do, I thought I was looking at a piece of fir-bark--one
of those amongst which it sat. I, in fact, looked for the eggs _upon_
the bird, for I knew the exact spot where they should be; but, as I
should have seen them, at once, owing to their light colour, I felt
sure they must be covered, and after gazing steadily, for some time,
all at once--by an optical delusion, as it seemed, rather than by
the passing away of one--the piece of fir-bark became the nightjar.
It was like a conjuring trick. The broad, flat head, from which the
short beak projects hardly noticeably, presented no special outline
for the eye to seize on, but was all in one line with the body. It
looked just like the blunt, rounded end, either of a stump, or of any
of the pieces of fir-bark that were lying about, whilst the dark brown
lines and mottlings of the plumage, besides that they blended with,
and faded into, the surroundings, had, both in pattern and colouring,
a great resemblance to the latter object; the lighter feathers exactly
mimicking those patches which are made by the flaking off of some of
the numerous layers of which the bark of the Scotch fir is composed.
This would only be of any special advantage to the bird when, as in the
present instance, it had laid its eggs amongst pieces of such bark,
fallen from the neighbouring Scotch fir-trees, and did it invariably
do so, a special protective resemblance might, perhaps, be admitted.
This, however, is not the case. It lays them, also, under beeches or
elsewhere, where neither firs nor fir-bark are to be seen.
Unless, therefore, it can be shown that a large majority of nightjars
lay, and have for a long time laid, their eggs in the neighbourhood
of the Scotch fir, the theory of a special resemblance in relation to
such a habit, due to the action of natural selection, must be given
up; as I believe it ought to be in some other apparent instances of
it, which have received more attention. Of course, there might be a
difference of opinion, especially if the bird were laid on a table, as
to the amount, or even the existence, of the resemblance which I here
insist upon. But I return to the essential fact. At the distance of two
paces I looked full at a nightjar sitting amongst flakes of fir-bark,
strewed about the sand, and, for some time, it appeared to me that it
was one of these. This is interesting, if we suppose, as I do, that
mere chance has brought about the resemblance, for here is a point
from which natural selection might easily go on towards perfection.
As I did make out the bird, at last, there is clearly more to be done.
It is, perhaps, just possible that we already see in the nightjar some
steps towards a special resemblance. The bird is especially numerous in
Norway, as I was told when I was there; and Norway is one great, pine
forest. However, not knowing enough in regard to its habitat, and the
relative numbers of individuals that resort to different portions of
it, to form an opinion on this point, I will suppose, in the meantime,
that its colouring has been made generally protective, in relation
to its incubatory habits; for the eggs are laid on the ground, and
commonly at the foot of a tree, stump, or bush--in the neighbourhood of
such objects, in fact, as have a more or less brownish hue.
It is during incubation that the bird would stand most in need of
protection, since it is then exposed, more or less completely, for a
great length of time. One bird, as far as I have been able to see,
sits on the eggs all day long, without ever once leaving them. Day,
however, is night to the nightjar, who not only sits on its eggs, but
sleeps, or, at least, dozes, on them as well. Drowsiness may, in this
case, have meant security both to bird and eggs; for the most sleepy
individuals would, by keeping still, have best safeguarded their
young, at all stages, as well as themselves, against the attacks of
small predatory animals. Flies used often to crawl over the face of
the bird I watched daily. They would get on its eyes; and once a large
bluebottle flew right at one of them. But beyond causing it just to
open or shut the eye, as the case might be, they produced no effect
upon the sleepy creature. The nightjar is a remarkably close sitter,
and both this special habit and its general drowsiness upon the nest
may have been fostered, at the same time, by natural selection. The
more usual view of the nightjar’s colouring is, I suppose, that it is
dusky, in harmony with night. But from what does a bird of its great
powers of flight require protection, either as against the attacks of
enemies or the escape of prey; and again, what colour, short of white,
would be a disadvantage to it, in the case of either, when _nox atra
colorem abstulit rebus_?
Questions of a similar nature may be asked in regard to the tiger,
lion, and other large feline animals, which, fearing no enemy, and
hunting their prey by scent, after dark, are yet supposed to be
protected by their coloration. These things are easily settled in the
study, where the habits of the species pronounced upon, not being
known, are not taken into account; but I may mention that my brother,
with his many years’ experience of wild beasts and their ways, and,
moreover, a thorough evolutionist, is a great doubter here. How, he
asks, as I do now, with him, can the lion be protected, in this way,
against the antelope, and the antelope against the lion, when the one
hunts, and the other is caught, by scent, after darkness has set in?
Of what use, for such a purpose, can colour or colour-markings be to
either of them? On the other hand, these go, in varying degrees, to
make up a creature’s beauty. Take, for instance, the leopard, jaguar,
or tiger.[7] Surely their coloration suggests adornment much more
obviously than assimilation; and though they hunt mostly, as I say,
by night, they are yet sufficiently diurnal to be able to admire
one another in the daytime. Darwin, who is often assumed to have
been favourable to the protective theory of coloration in the larger
animals, in instances where he was opposed to it, says this: “Although
we must admit that many quadrupeds have received their present tints,
either as a protection or as an aid in procuring prey, yet, with a host
of species, the colours are far too conspicuous, and too singularly
arranged, to allow us to suppose that they serve for these purposes.”
He then cites various antelopes, giving illustrations of two, and
continues: “The same conclusion may, perhaps, be extended to the
tiger, one of the most beautiful animals in the world, the sexes of
which cannot be distinguished by colour, even by the dealers in wild
beasts. Mr. Wallace believes that the striped coat of the tiger ‘so
assimilates with the vertical stems of the bamboo[8] as to assist
greatly in concealing him from his approaching prey.’ But this view
does not appear to me satisfactory.” (It seems opposed to the more
usual habits of the creature.) “We have some slight evidence that his
beauty may be due to sexual selection, for in two species of _felis_
the analogous marks and colours are rather brighter in the male than
in the female. The zebra is conspicuously striped, and stripes cannot
afford any protection on the open plains of South Africa.”[9] Yet, when
naturalists to-day refer every colour and pattern under the sun to the
principle of protection, the reviewers all agree that Darwin agrees
with them. Truly, nowadays, “_‘Darwin’ laudetur et alget_.”
The fact is that for some reason--I believe because it lessens the
supposed mental gap between man and other animals--Darwin’s theory of
sexual selection was, from the beginning, looked askance at; and even
those who may accept it, now, in the general, do so tentatively, and
with many cautious expressions intended to guard their own reputations.
This is not a frame of mind favourable to applying that theory, and,
consequently, all the applications and extensions go to the credit of
the more accepted, because less _bizarre_, one; for even if authorities
are mistaken here, they will, at least, have erred in the orthodox
groove, which is something. I believe, myself, that it is sexual
selection which has produced much of what is supposed to be due not
only to the principle of protective, but to that, also, of conspicuous,
or distinctive, coloration. Take, for instance, the rabbit’s tail. I
have never been able to make out that the accepted theory in regard to
it is borne out by the creature’s habits. Rabbits race and run not only
in alarm, but as an outcome of high spirits. How can the white tail
distinguish between these two causes; and if it cannot, why should it
be a sign to follow? One rabbit may indeed judge as to the state of
mind of another, but not by looking at the tail; and if too far off to
see anything else, it can form no opinion. Again, each rabbit has its
own burrow, and it does not follow that because one runs to it here,
another should there. Accordingly, I have noticed that white tails
in rapid motion produce no effect upon other tails, or their owners,
when these are some way off, but that rabbits, alarmed, make their
near companions look about them. Of course, in the case of a general
stampede, in the dusk, to the warren--from which numbers of the rabbits
may have strayed away--it is easy to imagine that the rearmost are
following the white tails of those in front of them; or rather that
these have given them the alarm, since all know the way to the warren.
But how can one tell that this is really so, seeing that the alarm in
such a case is generally due to a man stalking up? Would it not look
exactly the same in the case of prairie marmots, whose tails are not
conspicuously coloured? Young rabbits, it is true, would follow their
dams when they ran, in fear, to their burrows; not, however, unless
they recognised them, and this they could not do by the tail alone. If
they were near enough to recognise them, they would be able, probably,
to follow them by sight alone, tail or no tail, nor would another white
powder-puff be liable to lead them astray, as otherwise it might do.
With antelopes, indeed, which have to follow one another, so as not to
stray from the herd, a light-coloured patch, or wash upon the hinder
quarters, might be an advantage; but as some of the kinds that have[10]
it are handsomely ornamented on the face and body, and as the wash of
colour behind is often, in itself, not inelegant, why should not one
and all be for the sake of adornment, or, rather, is it not more likely
that they are so? No one, I suppose, who believes in sexual selection
at all, will be inclined to explain the origin of the coloured
posterior surface in the mandril, and some other monkeys, in any other
way. To me, having regard to certain primary facts in the sexual
relations of all animals, it does not appear strange that this region
should, in many species, have fallen under the influence of the latter
power. Can we, indeed, say, taking the Hottentots and some civilised
monstrosities of feminine costume that do most sincerely flatter them
into consideration, that it has not done so in the case of man?
The protective theory, as applied to animals that hunt, or are hunted,
by night, seems plausible only if we suppose that the enemies against
whom they are protected, are human ones. But even if man has been long
enough upon the scene to produce such modification, who can imagine
that he has had anything to do with the colouring of such an animal
as, say, the tiger, till recently much more the oppressor than the
oppressed, and, even now, as much the one as the other--in India, for
instance, or Corea, in which latter country things are certainly equal,
if we go by the Chinese proverb, which says, “Half the year the Coreans
hunt the tigers, and the other half the tigers hunt the Coreans.”
Tigers, indeed--especially those that are cattle-feeders--would
seem, often, to kill their prey towards evening, but when it is
still broad daylight. With regard, however, to the way in which they
accomplish this, I read some years ago, in an Indian sporting work, a
most interesting account of a tiger stalking a cow--an account full
of suggestiveness, and which ought to have, at once, attracted the
attention of naturalists, but which, as far as I know, has never since
been referred to. The author--whose name, with that of his work, I
cannot recall--says that he saw a cow staring intently at something
which was approaching it, and that this something presented so odd
an appearance that it was some time before he could make out what it
was. At last, however, he saw it to be a tiger, or, rather, the head
of one, for the creature’s whole body, being pressed to the ground,
with the fur flattened down, so as to make it as small as possible,
was hidden, or almost hidden, behind the head, which was raised, and
projected forward very conspicuously; so that, being held at about the
angle at which the human face is, it looked like a large, painted mask,
advancing along the ground in a very mysterious manner. At this mask
the cow gazed intently, as if spell-bound, seeming to have no idea of
what it was, and it was not till the tiger had got sufficiently near to
secure her with ease, that she took to her heels, only to be overtaken
and pulled down. Now here we have something worth all the accounts of
tiger-shootings that have ever been written, and all the tigers that
have ever been shot. So far from the tiger endeavouring to conceal
himself _in toto_, it would appear, from this, that he makes his great
brindled head, with its glaring eyes, a very conspicuous object, which,
as it is the only part of him seen or remarked, looks curious merely,
and excites wonder, rather than fear. I know, myself, how much nearer
to birds I am able to get, by approaching on my hands and knees, in
which attitude “the human form divine” is not at once recognised.
Therefore I can see no reason why the same principle of altering the
characteristic appearance should not be employed by some beasts of
prey, and long before I read this account I had been struck with the
great size of the head of some of the tigers in the Zoological Gardens.
The moral of it all, as it appears to me, is that, before coming to any
settled conclusion as to the meaning of colour and colour markings in
any animal, we should get accurate and minute information in regard to
such animal’s habits. As this is, really, a most important matter, why
should there not be scholarships and professorships in connection with
it? It is absurd that the only sort of knowledge in natural history
which leads to a recognised position, with letters after the name, is
knowledge of bones, muscles, tissues, &c. The habits of animals are
really as scientific as their anatomies, and professors of them, when
once made, would be as good as their brothers.
Space, after this disquisition, will not permit me to say much more
about the nightjars--only this, that they return each year to the same
spot, and have not only their favourite tree, but even their favourite
branch in it, to perch upon. I have seen one settle, after successive
flights, upon a particular point of dead wood, near the top of a small
and inconspicuous oak, surrounded by taller trees which had a much more
inviting appearance, and on coming another night, there were just the
same flights and settlings. It is not, however, my experience that the
eggs are laid, each year, just where they were the year before. It may
be so, as a rule, but there are certainly exceptions, and amongst them
were the particular pair that I watched.
[Illustration: ROOKS AT NEST]