Papers presented to the World's Congress on Ornithology/The Migration of Hirundo Rustica to South Africa
THE MIGRATION OF HIRUNDO RUSTICA TO SOUTH AFRICA.
BY DR. EMIL HOLUB, VIENNA.
It is commmonly known that the European Swallow winters in Northern Africa, but it may be known to few that by far the largest number of this species migrate to the southern portions of the Dark Continent.
Every year, from October to March, through the eleven years of my sojourn in South Africa, and in the very midst of the southern summer, I have seen these Swallows hunting up and down the endless plains, destroying vast numbers of the myriads of southern insects, and uniting every evening into swarms of thousands, in some spots of hundreds of thousands, to seek their resting-places for the night.
In the following I will refer to one of those sleeping-places, asking the kind reader to accompany me to that lonely spot, visited by me on a day in November twenty-five years ago. We are in the midst of an endless plain. Toward the east, hardly perceptible by its treeless banks, the Harts Spruit[1] takes its southwesterly course to the Vaal River, a right-hand tributary of the Kai Gariep or Orange River, the latter in its lower course being a natural boundary line of Cape Colony toward the north. The grassy cover of the plain is about one yard high, and the slender stems of this high grass, waving to and fro in the northwesterly breeze, are interwoven with numerous blossoms, showing all the colors which form a rainbow’s beauty. Everywhere on the immense flat, bounded by the blue sky of the horizon only, whereto we turn our eyes, and plainly to be seen from the small hill, an elevation formed by the white alluvial karoo tuff-stone, herds of game are visible. Large troops of the blessbuck (Damalis albifrons) are quietly grazing; small herds of the black gnu (Connochxtes gnu) are here and there enjoying their circular runs, the latter to hunters known as “wildebeest dances.” But most numerous of all are the graceful springbucks, Antidorcas euchore, which in herds of hundreds in all directions are to be seen; many of them, unruly in their playfulness, leap up eight feet above the ground, bounding one over the other.[2]
Among the antelopes and gnus, Cranes, single as well as in pairs and troops of fifty or more, are walking up and down, feeding upon the numerous locusts and upon the white ants—the nests of which latter, about two feet high and hemispherical, or in the form of tubes two to four feet high, are to be found in hundreds of thousands upon the Harts and Mo-lapo Spruit plains.[3]
Just in front of us and down below in the grassy plains the dark waters of a large pool glisten and quiver in the reddish shine of the subsiding sun . In its centre, this being the orifice of an underground cave, common to the dark-gray dolomite formation of these plains, the pool is of very great depth; otherwise it is shallow in its greatest extent, and such places are overgrown with a thicket of tall, rustling reeds. One of these abodes forms truly a centre of bird-life in the immense plain, so large in extent as not to be overglanced by the human eye, not even from the elevated position which we are occupying. This marsh, about 900 yards in diameter, with a deep rocky cavern in its centre, is worthy of the admiration of mankind; it is a place offering any amount of important observations upon bird-life to every lover of natural science, but it is especially attractive to an ornithologist who wishes to learn and to study, and who does not come to destroy birds and thus make his visit a mercenary matter.
The marsh is inhabited by numerous birds. Many species of singers and Finches, many more of wading and swimming birds, nest among the tall reeds, making this only marshy thicket in the vast plain their home for the whole year through; but there are others, like the European Swallow, different kinds of Herons, Storks, Cranes, and other Grallæ, Plectropterus gambensis and the Egyptian Goose (Chenalopex ægyptiacus), which pour in toward the night only, selecting this lonely spot to be their dormitory for the few hours up to the dawning day.
I consider the few days which I spent on the banks of this pool as some of the happiest ones which I experienced during my first African exploring trip of seven years’ duration; but one thing which I do deplore is that, having no boat, I was not able to explore the centre of the dark waters and those many small islands, formed of floating rushes and broken-down reeds, which are the real nesting-places of numerous pairs of Fulicula, and several species of Anas, Dendrocygna and Querquedula.
It is just an hour before sunset. In the reeds below, the great noise produced by so many feathered inhabitants keeps on, as during the whole day. Conspicuous more than others are the hundreds of pairs of bright red Finches (Pyromelana sundevalli) watching their nests, and having used two or three close reeds as pillars for each of them; different species of yellow-tinted Weavers (Ploceus and Hyphantornis) are the next ones audible with their voices; in which chorus a few troops of the beautiful Kafir Finches, the nicest South African Finch, merrily join. The male of this bird (Cheraprocne) adorns itself during the breeding season with a velvet-black coat, scarlet epaulettes, and an elongated tail, over a foot long, though the body of the bird is only about as large as that of a Thrush; the female being dressed in a darker and lighter shaded brown, the same color the male assumes during the winter, denoting its sex by the faded epaulettes only, which mark so brightly the black festive summer coat. All the noise made by these Passeres conirostres in unison with the whistling and the songs of real Oscines (Salicaria, Sylvia, Pratincola and others), and interrupted by the shrieks and squabbles, more or less loud and shrill, of the Grallæ and Natatores, offers a natural concert of a peculiar kind, hardly to be reproduced by the human tongue or by the most skilful pen. For moments only, when the rapacious Milvus ægyptiacus throws a shadow from his large wings upon the waters, the cries of love and enmity cease, to be renewed with the same vigor as soon as the rapacious bird of prey has disappeared. From all sides, from near and far, one by one, in pairs, in whole families, and in long lines or wedge-shaped arrays, Stanley Cranes (Tetrapteryx stanley anus), the beautiful Kafir or Crested Cranes (Balearica regulorum), and many species of Herons, the small and large white, the gray, the purple, the black-necked, and the Goliath, (Ardea garzetta, A. egretta, A. cinerea, A. purpurea, A. atricapilla and A. goliath), also white and black Storks (C. alba and C. nigra), are returning to their sleeping-place. Wild Geese and Ducks, Plovers (Chettusia coronata, Hoplopterus speriosus and others), even a pair of Hammerkopfs (Scopus umbretta), which all kept the whole or a part of the day in the vicinity of the marsh, are now coming along, walking slowly and still grazing like the geese and ducks, or running and playing (like Chettusia coronata), or taking short flights, all claiming a place in the waters of the pool. In other parts of South Africa, where no marshes are to be found, but large and very shallow salt lakes,[4] all the wading and swimming birds of the neighborhood flock every evening to these waters, so as to avoid nightly attacks of the many small robbers, as jackals, hyenas, earthwolves and polecats, which infest these plains of the South African high plateau.
During these observations of ours an hour has passed; the sun’s golden disk is just touching the western horizon; in the east the shadows of the coming night are visible. As our eyes glance over the blue slfy above, adorned here and there with a few light, feathery clouds, glad in the golden-crimson of the sun’s last farewell greetings, we perceive in the far distance, near the horizon and on all sides, a few darkish spots. Is it a delusion or not that they come nearer? We look hither and thither and it seems as if these spots become larger; they appear to approach. And they are approaching; they darken and are rapidly increasing in their breadth. Are they not swarms of locusts? Locusts? Hardly possible! No, they are not these ravenous insects. The locusts come with the wind and pass over in a single dark cloud, darkest just above the ground; but those approaching clouds come from all directions. Some fly very high in the air, others from twenty to fifty yards high, others again move—as you can see—along the wavy grass; and suddenly this one cloud—now surely it is a swarm of birds—swerves aloft. Birds! Behold,—are they all birds, these approaching clouds? Yes, they are, and, to our great surprise, small, dark birds. We watch two of these large swarms, which from due north are making straight for us. They pass abreast for a few moments; suddenly the one to the left turns high up, lowers itself just as suddenly, and now both swarms, turning toward each other, have united in a single great cloud. Wherever we look the swarms are fast approaching; the grand sight of the confluence of two multitudes of birds just witnessed repeats itself on all sides. Quicker, dear reader, than I am able to express to you in words, most of these living clouds, at times overshot with a gleam of reddish sheen, the reflection of some real clouds still beaming in crimson on the far western horizon, have united in ten large swarms—no, in eight only; and look, they are still uniting! Our cries cease; we remain silent for a few moments, and then a loud cheer rings through the air. The endless swarms of Swallows have united into a single mighty cloud. Who could count them? The air is filled with them and with the noise they make with wings and voices. The swarm of more than hundreds of thousands moves up and down, to and fro, lowering itself quickly down to the reeds and rising just as swiftly high up into the air; it moves like a living tidal wave and sounds like the rushing of mighty winds. And the voice of those countless feathered singers expresses their pleasure at having met again at the place of their night’s rest, which they have visited for weeks already and to which they will nightly resort for four months longer before departing for the far north.
The faded crimson on the western sky has disappeared. The evenings on these high African plateaus are very short. The night is fast approaching. Still the living, dark and noisy billow rolls up and down, a little less voluminous than before, as thousands have already joined the whistling Finches among the reeds. Suddenly the wave subsides, and turns sharply toward the grassy plain, as if it would leave the swamp for good; but just as suddenly it returns in a semicircle and striking the reeds sinks among them, not to rise again. The voices still keep on; no wonder that disputes arise among the Swallows themselves and also with the Finches regarding about three inches of space on the same reed stem. This noise keeps on for about a quarter of an hour, when it ceases. At last the weary birds have found a place to rest, and soon they are asleep. But do not think, dear reader, that with the retirement of the Swallows every sign of life has ceased in the dark marsh for the night. Though the night has set in, we soon hear peculiar low tones coming from the thicket of reeds. We hear the melancholy song of the Sylvias, the voices of the Night Herons and of the Bitterns, and from time to time the gurgling cry of the sentinel among the gray Cranes mingles with them, generally followed up by the cries of the whole troop of Cranes. Another Crane takes the watch until his cry again puts these large birds on the alert against the sly attacks of hyenas and jackals.
The day is dawning. The song of the gray Sylvias and the Bittern’s loud boom are soon drowned in the noise of the hundreds of thousands of Swallows which have just awakened, and in the loud cries of the large birds, which try at first a walk on the moist bank of the swamp, before they leave for the plains. Our friends, the Swallows, rise after a good deal of squabbling about the dreams of the night past; they leave in small swarms—as I think, those coming from certain European districts keeping together for the whole time of their African sojourn—and make at once for the different portions of that endless plain, on which they are accustomed to hunt day after day. But they do not rise high up in the air to fly in any particular direction; taking the proper course at first, they commence at once to search for food, reaching their proper hunting-field—may it be near or very far off—by thus flying low along the high grass, and taking with their breakfast the glittering drops of the morning dew to quench their thirst.
Who could count the millions of insects the swarms of Swallows which rest at this one marsh destroy in a single day on that South African plain? Count now all the sleeping-places; count now all the swarms of this most useful bird; consider also the number of days of our winter, during which the Swallows remain in the far south; and if you have never before meditated on a small bird’s life, you will acquire a new notion: that you harm yourself and your children if you injure this true small friend. You will then recognize in yourself a protector not only of the Swallow but of all useful birds, which were sent into the world to do good to mankind, and are therefore not to be killed for vanity’s sake.
- ↑ A spruit is a river flowing after heavy rainfalls for a few days or weeks only; most of the year such a river is dry, with the exception of some of the deepest places in its bed, which contain water for a few months.
- ↑ The gnus and blessbucks have since been annihilated; only a few springbucks remain.
- ↑ In this portion of southeastern British-Bechuanaland since the 18th of November, 1895, incorporated to the Cape Colony.
- ↑ Up to several miles in diameter, and from one to two and a half feet deep in the centre, some with a few sweet water springs on their banks. They are everywhere in country which has no communication with the ocean, and are commonly called “saltpans,” being the lowest places in southern portions of the high plateau—the reservoir for rain-water.
This work was published before January 1, 1929, and is in the public domain worldwide because the author died at least 100 years ago.
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