Part 19

The sunset hour is, I think, the most interesting at which to watch birds. They seem to be livelier then than at any other time of the day; they are certainly more loquacious. The dormitory of the crows, the mynas, or the green parrots is a perfect pandemonium. Whilst listening to the uproar one can only suppose each member of the colony to be bubbling over with animal spirits and intent on recounting to his fellows all the doings of the day.

Most people may be inclined to think that it is impossible to derive much pleasure from observing so common a bird as the sparrow. This is a mistake. Often and often have I watched with the greatest pleasure the roosting operations of this despised bird. I know of a row of bushes that forms the dormitory of hundreds of sparrows. To enable the reader to appreciate what follows, let me say that the hedge in question is only some twenty yards long, its height is not much greater than that of a man, it is nowhere more than eight feet in breadth, and is within a hundred yards of an inhabited bungalow. Less than six yards away from it is a well, fitted with a creaking Persian wheel, at which coolies are continually working.

If you happen to pass this hedge within an hour of sunset, you will hear issuing from it the dissonance of many sparrows’ voices. You stop to listen, and, as you wait, a flock of sparrows dives into the thicket. You look about to see whether any more are coming and observe nothing. Suddenly some specks appear in the air, as if spontaneously generated. In two seconds these are seen to be sparrows. Within half a minute of the time you first set eyes upon them they are already in the bushes. They are followed by another little flock of six or seven, and another and another. Flight after flight arrives in quick succession, each of which shoots into the roosting hedge. I use the word “shoot” advisedly, for no other term describes the speed at which they enter the bushes. Their flight, although so rapid, is not direct; it takes the form of a quavering zigzag. Some of the flocks do not immediately plunge into the bushes. They circle once, twice, thrice, or even oftener, before they betake themselves to their leafy dormitory. Sometimes part of a flight dive into the hedge immediately upon arrival, while the remainder circle round and then fling themselves into the bushes as though they were soldiers performing a well-practised manœuvre; the first bird to reach the bush entering at the nearest end, the next a little farther on, the third still farther, and so on, so that the last sparrow to arrive enters the hedge at the far end. Sometimes a flock perches for a time on a tree near by before entering the hedge. Those who have only noticed sparrows pottering about will scarcely be able to believe their eyes when they see the speed at which they approach the roosting place. For the moment they are transformed into dignified birds.

All this time those individuals already in the hedge are making a great noise. Their chitter, chitter, chitter never for a moment ceases or even diminishes in intensity. Once in the hedge, the sparrows do not readily leave it. There is much motion of the leaves and branches, and birds are continually popping out of one part of the bushes into another. It is thus evident that there is considerable fighting for places. If, while all this is going on, you walk up to part of the hedge and shake it, the birds disturbed will only fly a yard or two and at once settle elsewhere in the thicket.

Meanwhile the sun has nearly set; the coolies near by have ceased working and are kindling a fire within a couple of yards of the bushes. But the sparrows appear to ignore both them and their fire. Settling down for the night engrosses their whole attention.

As the sun touches the horizon the incoming flights of sparrows become fewer and fewer; and after the golden orb has disappeared only one or two belated stragglers arrive. Sparrows are early roosters. Something approaching three thousand of them are now perched in that small hedge, yet none are visible except those that pop in and out, when jockeyed out of positions they have taken up. But although only a few sparrows come in after the sun has set, it is not until fully fifteen minutes later that there is any appreciable abatement of the din. It then becomes more spasmodic; it ceases for half a second, to burst forth again with undiminished intensity.

Twenty minutes or so after sunset the clamour becomes suddenly less. It is now possible to discern individual voices. The noise grows rapidly feebler. It almost ceases, but again becomes louder. It then nearly stops a second time. Perhaps not more than twenty voices are heard. There is yet another outburst, but the twitterers are by now very sleepy. Suddenly there is perfect silence for a few seconds, then more feeble twittering, then another silence longer than the last.

It is not yet dark, there is still a bright glow in the western sky. The periods of silence grow more prolonged and the outbursts of twittering become more faint and of shorter duration.

It is now thirty-nine minutes after the sun has set and perfect stillness reigns. The birds must have all fallen asleep. But no! one wakeful fellow commences again. He soon subsides. It has grown so dark that you can no longer see the sparrow-hawk perched on a tree hard by. He took up his position there early in the evening, and will probably breakfast first thing to-morrow morning off sparrow!

You now softly approach the bushes until your face touches the branches. There are twenty or thirty sparrows roosting within fifteen inches of you. You cannot see any of them, but if you were to stretch forth your hand you could as likely as not catch hold of one. You disturb a branch and there is a rustling of a dozen pairs of wings, so close to you that your face is fanned by the wind they cause. You have disturbed some birds, but they are so sleepy that they move without uttering a twitter. You leave the bush and return an hour later. Perfect silence reigns. You may now go right up to the roosting hedge and talk without disturbing any of the three thousand birds. You may even strike a match without arousing one, so soundly do they sleep.

Those who wish to rid a locality of a superabundance of sparrows might well profit by the fact that the birds sleep so soundly in companies. Could anything be easier than to throw a large net over such a hedge and thus secure, at one fell blow, the whole colony?

THE GAY DECEIVER

The drongo cuckoo (Surniculus lugubris) is a bird of which I know practically nothing. I doubt whether I have ever seen it in the flesh. It is, of course, quite unnecessary to apologise for discoursing upon a subject of which one’s knowledge is admittedly nil. In this superficial age the most successful writers are those most ignorant of their subject. When you know only one or two facts it is quite easy to parade them properly, to set them forth to best advantage. They are so few and far between that there is no danger of their jostling one another or bewildering the reader. Then, if you are conversant only with one side of a question, you are able to lay down the law so forcibly, and the public likes having the law laid down for it, it does not mind how crude, how absurd, how impossible one’s sentiments are so long as one is cocksure of them and is not afraid to say so.

My lack of knowledge of the habits of the drongo cuckoo is, however, not my chief reason for desiring to write about it. I wish to discuss the bird because natural selectionists frequently cite it as bearing striking testimony to the truth of their theory, whereas it seems to me that it does just the opposite. Surniculus lugubris is, so far as I am able to judge, an uncompromising opponent of those zoologists who pin their faith to the all-sufficiency of natural selection to account for evolution in the organic world.

The drongo cuckoo is as like the king-crow as one pea is to another. This bird, says Blanford, “is remarkable for its extraordinary resemblance in structure and colourisation to a drongo or king-crow (Dicrurus). The plumage is almost entirely black, and the tail forked owing to the lateral rectrices being turned outwards.” Blanford further declares that the bird, owing to its remarkable likeness to the king-crow, is apt to be overlooked.

This being so, it is quite unnecessary for me to describe the drongo cuckoo; it is the image of a king-crow. But stay, perhaps there are some who do not know this last bird by sight. Such should make its acquaintance. They will find it sitting on the next telegraph wire they pass—a sprightly black bird, much smaller than the crow (with which it has no connection), possessing a long, forked tail. Every now and again it makes little sallies into the air after the “circling gnat,” or anything else insectivorous that presents itself. When you see such a bird you may safely bet on its being a king-crow; the off-chance of its proving a drongo cuckoo may be neglected by all but the ultra-cautious.

Not much is known of the habits of this cuckoo; but what we do know shows that, sometimes, at any rate, it makes the king-crow act as its nursemaid. Mr. Davison saw two king-crows feeding a young Surniculus. The consequence is that every book on natural history trots out our friend the drongo cuckoo as an example of mimicry. The mimicry is, of course, unconscious: it is said to be the result of the action of natural selection.

King-crows are, as every one knows, exceedingly pugnacious birds; at the nesting season both cock and hen are little furies, who guard the nursery most carefully and will not allow a strange species to so much as perch in the tree in which it is placed.

It is thus obvious that the cuckoo who elects to victimise a king-crow is undertaking a “big thing,” yet this is what Surniculus does. It accomplishes its aim by trickery; it becomes a gay deceiver, disguising itself like its dupe. Now I readily admit that the disguise may be of the utmost use to the Surniculus; I can well understand that natural selection will seize hold of the disguise when once it has been donned and possibly perfect it; but I cannot see how natural selection can have originated the disguise as such.

The drongo cuckoo may be called an ass in a lion’s skin, or a lion in an ass’s skin, whichever way one looks at things. When once the skin has been assumed natural selection may modify it so as better to fit the wearer; but more than this it cannot do.

I do not pretend to know the colour of the last common ancestor of all the cuckoos, but I do not believe that the colour was black. What, then, caused Surniculus lugubris to become black and assume a king-crow-like tail?

A black feather or two, even if coupled with some lengthening of the tail, would in no way assist the cuckoo in placing its egg in the drongo’s nest. Suppose an ass were to borrow the caudal appendage of the king of the forest, pin it on behind him, and then advance among his fellows with loud brays, would any donkey of average intelligence be misled by the feeble attempt at disguise? I think not. Much less would a king-crow be deceived by a few black feathers in the plumage of a cuckoo.

I do not believe that natural selection has any direct connection with the nigritude of the drongo cuckoo. It is my opinion that, so far as the struggle for existence is concerned, it matters little to an animal what its colour be. Every creature has to be some colour: what that actual colour is must depend upon a great many factors; among these we may name the metabolic changes that go on inside the animal, its hereditary tendencies, sexual selection, and natural selection. Is it natural selection that has caused the king-crow to be black? I trow not.

The drongo is black because it is built that way; its tendency is to produce black feathers. Just as some men tend to put on flesh, so also some species of birds tend to grow black plumage. In the case of the king-crow sexual selection has possibly contributed to the bird’s nigritude. It is possible that black is a colour that appeals to king-crow ladies. “So neat, you know; a bird always looks well in black, and a forked tail gives him such an air of distinction.”

As the hen drongo is a bird capable of looking after herself, even when incubating, there is no necessity for her to be protectively coloured. As I have repeatedly declared, one ounce of good solid pugnacity is a better weapon in the struggle for existence than many pounds of protective colouration.

Again, in the case of king-crows nigritude may be an expression of vigour, the outward and visible sign of strength.

Let me make myself clear. Suppose that in a race of savages those that had fair hair were stronger, bolder, more prolific, and more pushing than the dark-haired men. Fair hair, in some inexplicable way, always accompanied strength and the like. It is obvious that, under these conditions, the race would in time become fair-haired: the milder dark men would eventually be hustled out of existence. Fair hair would then be the outward expression of vigour: it would not be the cause of vigour, merely the accompaniment of it; nor would it be a direct product of natural selection. In the same way it is possible that among drongos nigritude is in some manner correlated with vigour. This idea is not altogether fanciful. Are there not horses of “bad colour”? Are not white “socks” a sign of weakness? Is not roan a colour indicative of strength and endurance in a horse?

May not the blackness and the forked tail of the drongo cuckoo have arisen in the same way as they arose in the king-crow? In each case it may be an accompaniment of vigour, or it may be the result of sexual selection. Mrs. Surniculus may have had similar tastes to Mrs. Dicrurus, and, since cuckoos seem to be very plastic birds, her tastes have been gratified. As another example of this plasticity I may cite Centropus phasianus—a cuckoo which is a very fair imitation of a pheasant.