The immense aggregations of flamingoes which, in wet seasons, throng the middle marismas can scarce be described. Our bird-islets lay so remote from the low-lying shores that no land whatever was in sight; but the desolate horizon that surrounded them was adorned by an almost unbroken line of pink and white that separated sea and sky over the greater part of the circle. On examining the different herds narrowly through binoculars, an obvious dissimilarity was discovered in the appearance of certain groups. One or two in particular seemed so much denser than the others; the narrow white line looked three times as thick, and in the centre gave the idea that the birds were literally piled upon each other. Felipe suggested that these flamingoes must be at their pajeréra, or breeding-place, and after a long wet ride we found that this was the case. The water was very deep, the bottom clinging mud; at intervals the laboured plunging of the mule was exchanged for an easier, gliding motion—he was swimming. The change was a welcome relief to man and beast; but the labours undergone during these aquatic rides eventuated in the loss of one fine mule, a powerful beast worth £60.
On approach, the cause of the peculiar appearance of the flamingo city from a distance became clearly discernible. Hundreds of birds were sitting down on a low mud-island, hundreds more were standing erect thereon, while others stood in the water alongside. Thus the different elevations of their bodies formed what had appeared a triple or quadruple line.
On reaching the spot, we found a perfect mass of nests. The low, flat mud-plateau was crowded with them as thickly as its space permitted. The nests had little or no height above the dead-level mud—some were raised an inch or two, a few might reach four or five inches in height, but the majority were merely circular bulwarks of mud barely raised above the general level, and bearing the impression of the bird’s legs distinctly marked upon the periphery. The general aspect of the plateau might be likened to a large table covered with plates. In the centre was a deep hole full of muddy water, which, from the gouged appearance of its sides, had probably supplied the birds with building material.
Scattered round the main colony were many single nests, rising out of the water and evidently built up from the bottom. Here and there two or three of these were joined together—“semi-detached,” so to speak. These isolated nests stood some eight inches above water-level, and as the depth exceeded a foot, their total height would be two feet or thereabouts, and their width across the hollowed top, some fifteen inches. None of the nests as yet contained eggs, and though we returned to the pajeréra on the latest day we were in its neighbourhood (May 11), they still remained empty. On both occasions many hundreds of flamingoes were sitting on the nests, and on the 11th we enjoyed excellent views at close quarters. Linked arm-in-arm with Felipe, and crouching low on the water to look as little human as possible, we had approached within seventy yards before the sentries first showed signs of alarm; and at that distance, with binoculars, observed the sitting flamingoes as distinctly as one need wish. The long red legs doubled under their bodies, the knees projecting slightly beyond the tail, and the graceful necks neatly curled away among their back feathers like a sitting swan, some heads resting on the breasts—all these points were unmistakable. Indeed, as regards the disposition of the legs in an incubating flamingo, no other attitude was possible since, in the great majority of cases, the nests were barely raised above the level of the mud-plateau. To sit astride on a flat surface is out of the question.
Inexplicable it seems that the flamingo, a bird that spends its life half knee-deep in water, should so long delay the period of incubation. For long ere eggs could be hatched, and young reared, the full summer heats of June and July would already have set in, water would have utterly disappeared, and the flamingoes be left stranded in a scorching desert of sun-baked mud.
Being unable ourselves to return to the marisma, we sent Felipe back on May 26, when he obtained eggs—long, white, and chalky, some specimens extremely rugged. Two is the number laid in each nest. In 1872 we had obtained six eggs taken on May 24, which may therefore, probably, be taken as the average date of laying. There remains, nevertheless, the bare possibility that eggs had been laid before our visit on May 9, but swept up meanwhile by egg-raiders.
The flamingo city “in being” above described was the first seen by ornithologists, and the observations we were enabled to make settled at last the position and mode of incubation of the flamingo.[49]