Animal Intelligence Part 28

Cuckoos are not the only birds which manifest the parasitic habit of laying their eggs in other birds' nests.

Some species of _Melothrus_, a widely distinct genus of American birds, allied to our starlings, have parasitic habits like those of the cuckoo; and the species present an interesting gradation in the perfection of their instincts. The s.e.xes of _Melothrus cadius_ are stated by an excellent observer, Mr.

Hudson, sometimes to live promiscuously together in flocks and sometimes to pair. They either build a nest of their own, or seize on one belonging to some other bird, occasionally throwing out the nestlings of the stranger. They either lay their eggs in the nest thus appropriated, or oddly enough build one for themselves on the top of it. They usually sit on their own eggs and rear their own young; but Mr. Hudson says it is probable that they are occasionally parasitic, for he has seen the young of this species feeding old birds of a distinct kind and clamouring to be fed by them.

The parasitic habits of another species of _Melothrus_, the _M. Canariensis_, are much more highly developed than those of the last, but are still far from perfect. This bird, as far as it is known, invariably lays its eggs in the nests of strangers, but it is remarkable that several together sometimes commence to build an irregular untidy nest of their own, placed in singularly ill-adapted situations, as on the leaves of a large thistle. They must, however, as far as Mr. Hudson has ascertained, complete a nest for themselves. They often lay so many eggs, from fifteen to twenty, in the same foster-nest, that few or none can possibly be hatched. They have, moreover, the extraordinary habit of pecking holes in the eggs, whether of their own species or of their foster-parents, which they find in the appropriated nests. They drop also many eggs on the bare ground, which are thus wasted. A third species, the _M.

precius_ of North America, has acquired instincts as perfect as those of the cuckoo, for it never lays more than an egg in a foster-nest, so that the young bird is securely reared. Mr. Hudson is a strong disbeliever in evolution, but he appears to have been so much struck by the imperfect instincts of the _Melothrus Canariensis_ that he quotes my words, and asks, 'Must we consider these habits not as especially endowed or created instincts, but as small consequences of one general law, namely transition?'[177]

Such are all the facts and considerations which I have to present with reference to the curious instinct in question. It will be seen that--with one doubtful or not sufficiently investigated exception, viz., that of cuckoos adapting the colour of their eggs to that of the eggs of the foster-parents--there is nothing connected with these instincts that presents any difficulty to the theory of evolution. We may, perhaps, at first sight wonder why some counteracting instinct should not have been developed by the same agency in the birds which are liable to be thus duped; but here we must remember that the deposition of a parasitic egg is, comparatively speaking, an exceedingly rare event, and therefore not one that is likely to lead to the development of a special instinct to meet it.

_General Intelligence._

Under this heading I shall here, as in the case of this heading elsewhere, string together all the instances which I have met with, and which I deem trustworthy, of the display of unusually high intelligence in the cla.s.s, family, order, or species of animals under consideration--the object of this heading in all cases being that of supplying, by the facts mentioned beneath it, a general idea of the upper limit of intelligence which is distinctive of each group of animals.

That birds recognise their own images in mirrors as birds there can be no question. Houzeau, who records observations of his own in this connection with parrots,[178] adds that dogs are more difficult to deceive by mirrors in this way than birds, on account of their depending so much upon smell for their information. No doubt individual differences are to be met with in animals of both cla.s.ses, and much depends on previous experience. Young dogs, or dogs which have never seen a mirror before, are not, as a rule, difficult to deceive, even though they have good noses. I myself had a setter with an excellent nose, who on many repeated occasions tried to fight his own image, till he found by experience that it was of no use. As to birds, I have seen canaries suppose their own images to be other canary birds, and also the reflection of a room to be another room--the birds flying against a large mirror and falling half stunned. I mention the latter circ.u.mstance because it afforded evidence of the superior intelligence of a linnet, which on the same occasion dashed itself against the mirror once, but never a second time, while the canaries did so repeatedly.

Mrs. Frankland, in 'Nature' (xxi., p. 82), gives the following account of a bullfinch paying more attention to a portrait of a bullfinch than to his own image in a mirror, which is certainly remarkable; and as the fact seems to have been observed repeatedly, it can scarcely be discredited:

The following is a curious instance of discrimination which I have observed in my bullfinch. He is in the habit of coming out of his cage in my room in the morning. In this room there is a mirror with a marble slab before it, and also a very cleverly executed water-colour drawing of a hen bullfinch, life size.

The first thing that my bullfinch does on leaving his cage is to fly to the picture (perching on a vase just below it) and pipe his tune in the most insinuating manner, accompanied with much bowing to the portrait of the hen bullfinch. After having duly paid his addresses to it, he generally spends some time on the marble slab in front of the looking-gla.s.s, but without showing the slightest emotion at the sight of his own reflection, or courting it with a song. Whether this perfect coolness is due to the fact of the reflection being that of a c.o.c.k bird, or whether (since he shows no desire to fight the reflected image) he is perfectly well aware that he only sees himself, it is difficult to say.

That birds possess considerable powers of imagination, or forming mental pictures of absent objects, may be inferred from the fact of their pining for absent mates, parrots calling for absent friends, &c. The same fact is further proved by birds dreaming, a faculty which has been noticed by Cuvier, Jerdon, Thompson, Bennet, Houzeau, Bechstein, Lindsay, and Darwin.[179]

The facility with which birds lend themselves to the education of the show-man is certain evidence of considerable docility, or the power of forming novel a.s.sociations of ideas. Thus, according to Bingley,--

Some years ago the Sieur Roman exhibited in this country the wonderful performances of his birds. These were goldfinches, linnets, and canary birds. One appeared dead, and was held up by the tail or claw without exhibiting any signs of life. A second stood on its head, with its claws in the air, &c., &c.[180]

And many years ago there was exhibited a very puzzling automaton, which, although of very small size and quite isolated from any possibly mechanical connection with its designer, performed certain movements in any order that the fancy of the observers might dictate. The explanation turned out to be that within the mechanism of the figure there was a canary bird which had been taught to run in different directions at different words or tones of command, so by its weight starting the mechanism to perform the particular movement required.

The rapidity with which birds learn not to fly against newly erected telegraph wires, displays a large amount of observation and intelligence. The fact has been repeatedly observed. For instance, Mr.

Holden says:--

About twelve years ago I was residing on the coast of county Antrim, at the time the telegraph wires were set up along that charming road which skirts the sea between Larne and Cushendall. During the winter months large flocks of starlings always migrated over from Scotland, arriving in the early morning. The first winter after the wires were stretched along the coast I frequently found numbers of starlings lying dead or wounded on the road-side, they having evidently in their flight in the dusky morn struck against the telegraph wires, not blown against them, as these accidents often occurred when there was but little wind. I found that the peasantry had come to the conclusion that these unusual deaths were due to the flash of the telegraph messages killing any starlings that happened to be perched on the wires when working.

Strange to say that throughout the following and succeeding winters hardly a death occurred among the starlings on their arrival. It would thus appear that the birds were deeply impressed, and understood the cause of the fatal accidents among their fellow-travellers the previous year, and hence carefully avoided the telegraph wires; not only so, but the young birds must also have acquired this knowledge and perpetuated it, a knowledge which they could not have acquired by experience or even instinct, unless the instinct was really inherited memory derived from the parents whose brains were first impressed by it.[181]

Similar facts are given in Buckland's 'Curiosities of Natural History,'[182] and I have myself known of a case in Scotland where a telegraph was erected across a piece of moorland. During the first season some of the grouse were injured by flying against the wires, but never in any succeeding season. Why the young birds should avoid them without having had individual experience may, I think, be explained by the consideration that in birds which fly in flocks or coveys, it is the older ones that lead the way. This explanation would not, of course, apply to birds which fly singly; but I am not aware that any observations have gone to show that the young of such birds avoid the wires.

I quote the following exhibition of intelligence in an eagle from Menault:--

The following account of the patience with which a golden eagle submitted to surgical treatment, and the care which it showed in the gradual use of the healing limb, must suggest the idea that something very near to prudence and reason existed in the bird. This eagle was caught in a fox-trap set in the forest of Fontainebleau, and its claw had been terribly torn. An operation was performed on the limb by the conservators of the Zoological Gardens at Paris, which the n.o.ble bird bore with a rational patience. Though his head was left loose, he made no attempts to interfere with the agonising extraction of the splinters, or to disturb the arrangements of the annoying bandages. He seemed really to understand the nature of the services rendered, and that they were for his good.[183]

Speaking of the Urubu vultures, Mr. Bates says:--

They a.s.semble in great numbers in the villages about the end of the wet season, and are then ravenous with hunger. My cook could not leave the open kitchen at the back of the house for a moment whilst the dinner was cooking, on account of their thievish propensities. Some of them were always loitering about, watching their opportunity, and the instant the kitchen was left unguarded, the bold marauders marched in and lifted the lids of the saucepans with their beaks to rob them of their contents. The boys of the village lie in wait, and shoot them with bow and arrow; and vultures have consequently acquired such a dread of these weapons, that they may be often kept off by hanging a bow from the rafters of the kitchen.[184]

Mrs. Lee, in her 'Anecdotes', says that one day her gardener was struck by the strange conduct of a robin, which the man had often fed. The bird fluttered about him in so strange a manner--now coming close, then hurrying away, always in the same direction--that the gardener followed its retreating movements. The robin stopped near a flower-pot, and fluttered over it in great agitation. It was soon found that a nest had been formed in the pot, and contained several young.

Close by was a snake, intent, doubtless, upon making a meal of the brood.

The following appeared in the 'Gardener's Chronicle' for Aug. 3, 1878, under the initials 'T. G.' I wrote to the editor requesting him to supply me with the name of his correspondent, and also to state whether he knew him to be a trustworthy man. In reply the editor said that he knew his correspondent to be trustworthy, and that his name is Thomas Guring:--

About thirty years ago the small market town in which I reside was skirted by an open common, upon which a number of geese were kept by cottagers. The number of the birds was very great... . Our corn market at that time was held in the street in front of the princ.i.p.al inn, and on the market day a good deal of corn was scattered from sample bags by millers. Somehow the geese found out about the spilling of corn, and they appear to have held a consultation upon the subject... . From this time they never missed their opportunity, and the entry of the geese was always looked for and invariably took place. On the morning after the market, early, and always on the proper morning, fortnightly, in they came cackling and gobbling in merry mood, and they never came on the wrong day. The corn, of course, was the attraction, but in what manner did they mark the time? One might have supposed that their perceptions were awakened on the market day by the smell of corn, or perhaps by the noise of the market traffic; but my story is not yet finished, and its sequel is against this view. It happened one year that a day of national humiliation was kept, and the day appointed was that on which our market should have been held. The market was postponed, and the geese for once were baffled. There was no corn to tickle their olfactory organs from afar, no traffic to appeal to their sense of hearing.

I think our little town was as still as it usually is on Sundays... . The geese should have stopped away; but they knew their day, and came as usual... . I do not pretend to remember under what precise circ.u.mstances the habit of coming into the street was acquired. It may have been formed by degrees, and continued from year to year; but how the old birds, who must have led the way, marked the time so as to come in regularly and fortnightly, on a particular day of the week, I am at a loss to conceive.

Livingstone's 'Expedition to the Zambesi, 1865,' p. 209, gives a conclusive account of the bird called the honey-guide, which leads persons to bees' nests. 'They are quite as anxious to lure the stranger to the bees' hive as other birds are to draw him away from their own nests.' The object of the bird is to obtain the pupae of the bees which are laid bare by the ravaging of the nest. The habits of this bird have long been known and described in books on popular natural history; but it is well that the facts have been observed by so trustworthy a man as Livingstone. He adds, 'How is it that members of this family have learned that all men, white and black, are fond of honey? 'We can only answer, by intelligent observation in the first instance, pa.s.sing into individual and hereditary habit, and so eventually into a fixed instinct.

Brehm relates an instance of cautious sagacity in a pewit. He had placed some horsehair snares over its nest, but the bird seeing them, pushed them aside with her bill. Next day he set them thickly round the nest; but now the bird, instead of running as usual to the nest along the ground, alighted directly upon it. This shows a considerable appreciation of mechanical appliances, as does also the following.

Mrs. G. M. E. Campbell writes to me:--

At Ardgla.s.s, co. Down, Ireland, is a long tract of turf coming to the edge of the rocks overhanging the sea, where cattle and geese feed; at a barn on this tract there was a low enclosure, with a door fastening by a hook and staple to the side-post: when the hook was out of the staple, the door fell open by its own weight. I one day saw a goose with a large troop of goslings coming off the turf to this door, which was secured by the hook being in the staple. The goose waited for a minute or two, as if for the door to be opened, and then turned round as if to go away, but what she did was to make a rush at the door, and making a dart with her beak at the point of the hook nearly threw it out of the staple; she repeated this manoeuvre, and succeeded at the third attempt, the door fell open, and the goose led her troop in with a sound of triumphant chuckling. How had the goose learned that the force of the rush was needful to give the hook a sufficient toss?

Mrs. K. Addison sends me the following instance of the use of signs on the part of an intelligent jackdaw. The bird was eighteen months old, and lived in some bushes in Mrs. Addison's garden. She writes:--

I generally made a practice of filling a large basin which stands under the trees every morning for Jack's bath. A few days ago I forgot this duty, and was reminded of the fact in a very singular manner.

Another of my daily occupations is to open my dressing-room shutters about eleven o'clock of a morning. Now these said shutters open almost on to the trees where Jack lives. The day I forgot his bath, when I opened the shutters I found my little friend waiting just outside them, as though he knew that he should see me there; and when he did he placed himself immediately in front of me, and then shook himself and spread out his wings just as he always does in his bath. The action was so suggestive and so unmistakable, that I spoke just as I would have done to a child--'Oh yes, Jack, of course you shall have some water.'

Mr. W. W. Nichols writes to 'Nature:'--

The Central Prison at Agra is the roosting-place of great numbers of the common blue pigeon; they fly out to the neighbouring country for food every morning, and return in the evening, when they drink at a tank just outside the prison walls. In this tank are a large number of fresh-water turtles, which lie in wait for the pigeons just under the surface of the water and at the edge of it. Any bird alighting to drink near one of these turtles has a good chance of having its head bitten off and eaten; and the headless bodies of pigeons have been picked up near the water, showing the fate which has sometimes befallen the birds. The pigeons, however, are aware of the danger, and have hit on the following plan to escape it. A pigeon comes in from its long flight, and, as it nears the tank, instead of flying down at once to the water's edge, will cross the tank at about twenty feet above its surface, and then fly back to the side from which it came, apparently selecting for alighting a safe spot which it had remarked as it flew over the bank; but even when such a spot has been selected the bird will not alight at the edge of the water, but on the bank about a yard from the water, and will then run down quickly to the water, take two or three hurried gulps of it, and then fly off to repeat the same process at another part of the tank till its thirst is satisfied.

I had often watched the birds doing this, and could not account for their strange mode of drinking till told by my friend the superintendent of the prison, of the turtles which lay in ambush for the pigeons.

As a still more remarkable instance of the display of intelligence by a bird of this species, I shall quote the following observation of Commander R. H. Napier, also published in 'Nature' (viii., p. 324):--

A number of them (pouters) were feeding on a few oats that had been accidentally let fall while fixing the nose-bag on a horse standing at bait. Having finished all the grain at hand, a large 'pouter' rose, and flapping its wings furiously, flew directly at the horse's eyes, causing the animal to toss his head, and in doing so, of course shake out more corn. I saw this several times repeated--in fact, whenever the supply on hand had been exhausted... . Was not this something more than instinct?

The following display of intelligence on the part of swallows is communicated to me by Mr. Charles Wilson. It can scarcely be attributed to accident, and does not admit of mal-observation. My informant says:--

Two swallows were building a nest in the verandah of a house in Victoria, but as their nest was resting partly on a bell-wire, it was by this means twice pulled down. They then began afresh, making a tunnel through the lower part of the nest, through which the wire was able to act without doing damage.

Another gentleman writes me of another use to which he has observed swallows put the artifice of building tunnels. Being molested by sparrows which desired to take forcible possession of their nest, a pair of swallows modified the entrance of the latter, so that instead of opening by a simple hole under the eaves of a house, it was carried on in the form of a tunnel.

Linnaeus says that the martin, when it builds under the eaves of houses, sometimes is molested by sparrows taking possession of the nest. The pair of martins to which the nest belongs are not strong enough to dislodge the invaders; but they convoke their companions, some of whom guard the captives, whilst others bring clay, close up the entrance of the nest, and leave the sparrows to die miserably. This account has been to a large extent independently confirmed by Jesse, who seems not to have been acquainted with the statement of Linnaeus. He writes:--

Swallows seem to entertain the recollection of injury, and to resent it when an opportunity offers. A pair of swallows built their nest under the ledge of a house at Hampton Court. It was no sooner completed than a couple of sparrows drove them from it, notwithstanding the swallows kept up a good resistance, and even brought others to a.s.sist them. The intruders were left in peaceable possession of the nest, till the two old birds were obliged to quit it to provide food for their young. They had no sooner departed than several swallows came and broke down the nest; and I saw the young sparrows lying dead on the ground. As soon as the nest was demolished, the swallows began to rebuild it.[185]

The same author gives the following and somewhat similar case:--

A pair of swallows built their nest against one of the first-floor windows of an uninhabited house in Merrion Square, Dublin. A sparrow, however, took possession of it, and the swallows were repeatedly seen clinging to the nest, and endeavouring to gain an entrance to the abode they had erected with so much labour. All their efforts, however, were defeated by the sparrow, who never once quitted the nest. The perseverance of the swallows was at length exhausted: they took flight, but shortly afterwards returned, accompanied by a number of their congeners, each of them having a piece of dirt in its bill. By this means they succeeded in stopping up the hole, and the intruder was immured in total darkness. Soon afterwards the nest was taken down and exhibited to several persons, with the dead sparrow in it. In this case there appears to have been not only a reasoning faculty, but the birds must have been possessed of the power of communicating their resentment and their wishes to their friends, without whose aid they could not thus have avenged the injury they had sustained.[186]

That birds sometimes act in concert may also be gathered from the following observations recorded by Mr. Buck:--

I have constantly seen a flock of pelicans, when on the feed, form a line across a lake, and drive the fish before them up its whole length, just as fishermen would with a net.[187]

The following is extracted from Sir E. Tennent's 'Natural History of Ceylon,' and displays remarkable intelligence on the part of the crows in that island:--

One of these ingenious marauders, after vainly att.i.tudinising in front of a chained watch-dog, that was lazily gnawing a bone, and after fruitlessly endeavouring to divert his attention by dancing before him, with head awry and eye askance, at length flew away for a moment, and returned bringing a companion which perched itself on a branch a few yards in the rear. The crow's grimaces were now actively renewed, but with no better success, till its confederate, poising itself on its wings, descended with the utmost velocity, striking the dog upon the spine with all the force of its strong beak. The ruse was successful; the dog started with surprise and pain, but not quickly enough to seize his a.s.sailant, whilst the bone he had been gnawing was s.n.a.t.c.hed away by the first crow the instant his head was turned. Two well-authenticated instances of the recurrence of this device came within my knowledge at Colombo, and attest the sagacity and powers of communication and combination possessed by these astute and courageous birds.