In the Wilds of South America

by Leo E. Miller

One has the first view of the Rio Grande from the top of a rocky mountain nine thousand five hundred feet high, of which we reached the summit a few hours after leaving Pucará. Far below lay the dull, brown ribbon of water, looking like a painted streak across a grayish background. The descent to the watercourse is so abrupt that in many instances the trail consisted of a succession of steps hewn into the rock; toiling down the tortuous trail was life-sapping work for the pack-animals; we relieved the riding animals by walking. Downward, always downward, led the indistinct way, seemingly into a bottomless abyss. The mountainside is dry and cheerless; no dainty flower or blade of grass relieves the grim desolation of desert dust and shattered rock, and even the few grayish, stunted cacti seem to shrivel and die in the burning glare of a hostile sun. After hours that seemed more like days we arrived at the dry bed of a narrow stream and followed down its angular course. The aneroid showed that we were exactly one mile lower than our starting-point, but still the river seemed like a mirage, near, yet unattainable.

Although the declivity was now gentler, the lofty walls of gray sandstone flanking the dismal canyon through which we rode shut off any ventilating breeze that chanced to pass above, and made a stifling oven of the narrow fissure. For two hours we travelled over the rock-strewn stream-bed, and then suddenly entered a narrow belt of mimosas and cacti; the Rio Grande flows through the centre of the green little valley.

Although the river had appeared peaceful enough from the summit five thousand seven hundred feet above, we found it to be a wide, brown sheet of ruffled water racing over a boulder-encumbered bed. Our mule-drivers were filled with alarm and dared not venture into the treacherous flood. It was as we had feared; the spring rains had begun in the mountains, and the surplus water was rapidly swelling the lowland streams. While we were debating on the proper course to pursue, an Indian youth chanced along and consented to guide us to a ford about half a mile up-stream. Arrived at the spot, he stripped and waded cautiously into the river, which here spread over a wide bar. Fortunately the water was not over four feet deep; the youth returned to the bank and led the mules across one by one. When the river is too high to ford, the natives use tub-shaped boats made of ox-hide in which to cross; there is no way of controlling the craft, so the current may carry them a mile or so below the starting-point before it reaches the other side.

The water of the river was unfit for drinking. It contains about thirty per cent solid matter, although the reason for this was that it was rising rapidly and bringing down a great quantity of sand from the mountain.

Numbers of small ravines emerge from the barren slopes flanking the Rio Grande, and streams of inconsiderable size pour their water into the larger artery. All these openings are filled with brush and low trees; we followed up one of them and, within a few hours, reached a habitation called Bella Vista. The shambling structure stood on the edge of a clearing planted in sugar-cane. Dense jungles of wild cane and brush bounded the plantation. As I was already convinced that the Rio Grande is the avenue up which the chaco bird-life was penetrating into the higher regions, we determined to remain at Bella Vista sufficiently long to substantiate my views; it required only one day for this purpose. The species that had been found in limited numbers farther up, and that seemed to belong to a strange fauna, exist in abundance at Bella Vista; among them are brown-shouldered orioles, white anis (Guira), fork-tailed goatsuckers, white-throated toucans (Ramphastos) and many others.

Pigeons (Leptoptila) were so numerous that they suffered for lack of food. I am unable to say whether there had been an abnormal increase in the number of the species, or if the food-supply was unusually low; but one thing is certain—they were in a very emaciated condition and some of them had become so weakened that flight was impossible, and they fell an easy prey to the natives or predatory animals. I also noticed that all the pigeons were infested with parasites, but the weaker individuals were covered with them, including many winged, fly-like bird-ticks (Hippoboscidæ) that skipped among the feathers at bewildering speed, and finally flew away with a loud buzz; sometimes the repulsive insects settled on our hands or faces, when it was almost impossible to displace them, owing to their agile movements and to their clinging ability caused by the hooks on their feet.

This furnished a very good illustration of the survival of the fittest, and one that I believe is typical of what happens in many instances. Owing, perhaps, to unusual or long-continued favorable conditions, the species had become exceedingly numerous. So long as there was no shortage in the food-supply, the birds were able to hold their own and keep increasing; but, as the season of famine approached, as I believe it must occasionally do, though not necessarily at regular intervals, the weaker individuals were the first to feel the pinch of a reduced subsistence which automatically rendered them still less suited to obtain a livelihood. Their rapidly failing vigor also prevented them from coping with their natural enemies—whether parasitic or predaceous, so that they were soon eliminated and only those that entered the struggle in the strongest, healthiest condition stood a reasonable show of surviving.

While tramping through the cane-thickets, we found the nest of a pair of red-breasted thrushes. Both parent birds fluttered over our heads and with loud, angry cries expressed their resentment and anxiety. The nest was betrayed by the birds’ very actions. It was cunningly concealed in a dense tangle of leaves and creepers, and was not unlike that made by our own robin; but the three eggs were heavily spotted with brown instead of being of a plain blue color.

When dusk overtook us on the first day out of Pescado, thirty-six miles southeast of Bella Vista, we were riding over a grass-covered plateau with a stream flowing along one side of it. It was therefore unnecessary to seek an Indian dwelling for the purpose of securing forage. We picketed the mules, and slept out in the open. The next morning a Quechua woman with a fowl under her arm passed along the trail; we asked her the price of the bird, as we suspected that she was taking it to some village to sell. “Four bolivianos,” she replied promptly. The mule-driver remarked, very emphatically, that the price was exorbitant. “But,” she protested, “this is a game-cock. It is a good fighter and can whip any rooster in the country.” The arriero then informed her that we wanted the rooster to eat, and not to fight. “Oh,” said the woman, “that is another matter; sixty centavos,” and the sale was concluded without further argument.

Apparently the birds of the highlands were nesting. We saw numbers of newly constructed nests in the cacti and small-leaved vegetation; they belonged to mocking-birds, pigeons, and finches; but only a few of them contained eggs. The Indians had filled many of the little domiciles with stones before they were completed in an attempt to prevent an increase in the numbers of birds. Large flocks of several species gather in the grain-fields during the fall months and exact rather a heavy tribute, and it is for this reason that the Indians try to prevent their increase.