Chapter VII on the afternoon of the 9th of May.

As there stated, the immense aggregations of flamingoes in those middle marismas, surrounded the horizon in an almost unbroken line. But, on examining the different herds narrowly with the binocular, there was an obvious dissimilarity in the appearance of certain groups. One or two in particular seemed so much denser than the others: the narrow white line appeared at least three times as thick, and in the centre looked as if the birds were literally piled upon each other. Felipe suggested that these birds must be at their _pajeréra_, or breeding-place, and after a long wet ride we found this was so. The water was very deep, the bottom clinging mud: at intervals, for a hundred yards or so, 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: the sensation of sitting a swimming animal is not unpleasant, but it will give some idea of the labours undergone in these aquatic rides in the marismas in May, 1883, if we add that a fine mule, a powerful beast worth £60, succumbed to the effects of the fortnight's work.

On a nearer approach, the cause of the peculiar appearance of the herd from a distance became clearly discernible. Many of the birds were sitting down on a low mud-island. Some were standing upon it: and others again were standing in the water. 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. These nests had little or no height above the flat surface of mud--some were raised an inch or two, a few might be five or six inches in height; but the majority were merely circular bulwarks of mud barely raised above the general level, and having the impression of the bird's legs distinctly marked upon them. The general aspect of the plateau was not unlike 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, appeared to be used as a reservoir for nest-making materials.

Scattered all round this main colony were numerous 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 separate nests stood six or eight inches above water-level, and as the depth was rather over a foot, the total height of the nests would be some two feet or thereabouts, and their width across the hollow top some fifteen inches. None of these nests as yet contained any eggs, and though I returned to the _pajaréra_ on the latest day I was in its neighbourhood (May 11th) they still remained empty. On both occasions many hundreds of flamingoes were sitting on the nests, and on the 11th we had a good view of them at close quarters. Linked arm-in-arm with Felipe, and crouching low on the water to look as little human as possible, we approached within some seventy yards before their sentries showed signs of alarm: and at that distance, with the glass, observed the sitting birds as distinctly as one need wish. The long red legs doubled under their bodies, the knees projecting as far as, or beyond the tail, and their graceful necks neatly curled away among their back-feathers like a sitting swan, with the heads resting on their breasts--all these points were unmistakable. Indeed, as regards the disposition of their legs, it is hardly necessary to point out that in the great majority of cases (the nests being hardly raised above the level of the mud) no other position was possible--to sit _astride_ on a _flat_ surface is out of the question.

Still none of the crowded nests contained a single egg. How strange it is that the flamingo, a bird which never seems happy unless half-way up to his knees in water, should so long delay the period of incubation: for, long before eggs could be laid and hatched in these nests and the young reared, the full summer-heats of June and July would have set in, the water would have entirely disappeared, and the flamingoes would be left stranded in the midst of a scorching desert of dry, sun-baked mud.

Being unable myself to return to the marisma, I sent Felipe back there on the 26th of May, when he obtained eggs--long, white and chalky, some specimens extremely rough. Two is the number laid in each nest. In 1872 the writer obtained eggs taken on May 24th, which is therefore, probably, about the average date of laying. Owing to the late period at which incubation takes place, we have not had an opportunity of examining the young flamingoes when newly-hatched, or of endeavouring to solve the biological problems which appear to cluster round their adolescent anatomy. In June and July, 1872, the writer spent some time in the marisma, but unfortunately was not aware, at that time, of the interest attaching to these points.

According to native accounts, very few young flamingoes are ever reared in Spain. Though in wet seasons eggs are laid in thousands (they are sold by boatloads in the neighbouring villages), yet few, if any, of the young Spanish flamingoes reach maturity--possibly by reason of their lateness in nesting, and the rapid changes in the state of the water in the marisma.

In the spring of 1891, after an exceptionally severe winter in Spain, and with comparatively little water in the marisma, flamingoes were remarkably scarce, and we believe that none bred in Andalucia that year.

Since the author's description of the nesting habits of the flamingo first appeared in the _Ibis_ (January, 1884), its accuracy has been corroborated by independent observations made on the West Indian island of Abaco by His Excellency (now Sir) H. H. Blake, when Governor of the Bahamas. The value of the corroboration is enhanced by the fact that the above-named gentleman was unaware at the time he wrote that the long-vexed question had already, three years previously, been solved: and his graphic description in the _Nineteenth Century_ for December, 1887, is, as regards facts, almost identical with the present writer's account of a similar scene narrated in the _Ibis_ for January, 1884.

One other point before we leave the flamingo and its haunts. We have seen it stated that the brilliant colours of the flamingo do but reflect the brilliancy of its environment--that these bright colours have been acquired through the æsthetic tastes of the bird and by "selective preference"; then, proceeding to enlarge on a "fascinating theory," its expounder goes on from particular to general, and to demonstrate that this Darwinian principle is generally operative in ornithic coloration. Whether birds in general have or have not æsthetic tastes in the matter of coloration or ornament, we are not prepared to say: but to our less imaginative minds it is a question whether there exists in nature a shred of real evidence in support of such a hypothesis. The flamingo truly has a brilliant plumage, but _never_ a brilliant environment. No one who has been intimately acquainted with these birds in their haunts could have conceived such a sentiment; for anything less brilliant than the bleak and tawny monotony which characterizes the chosen homes of the flamingo it would be impossible to imagine. The flamingo itself, indeed, is the one solitary speck of pure bright colour amidst the broad leagues of mud and muddy water which it so conspicuously ornaments. Other birds are there, it is true, but to them the same remark applies. They, also, are as bright, pure and conspicuously different from their environment as are the flamingoes. What more exquisite examples of bright, spotless beauty amidst strongly contrasted surroundings than the stilts and avocets, the lovely southern herons, egrets and spoonbills, the gulls and marsh-terns? These are but a handful of examples fatal to such a theory, and they could easily be multiplied indefinitely.

That many brilliant bird-forms affect brilliant surroundings, that the fauna of the cold and colourless north in general lacks the gorgeous hues of certain denizens of the tropics, or, again, that many creatures possess hues assimilated to the general tone of their destined haunts--all these are _facts_ which we readily recognize. But are such facts much more than coincidences? Or is it wise to deduce any binding rules or axiom therefrom? As regards protective assimilation in colour, that is quite a different thing: its advantages are self-evident, and its application more or less universal throughout the animal-world, but it is hardly to the point. Protective coloration we recognize and understand--it is an every-day phenomenon--but æsthetic tastes in colour we utterly reject.

The composition of the human mind is undoubtedly speculative: and to those of deep thought, as distinguished from others the bent of whose energies tends rather towards action, the temptation to theorize--to venture on the dangerous regions of inference and deduction--appears irresistible. The contemplative thinker formulates theories the apparent beauty of which fascinate his imagination. Collateral evidence which seems to substantiate, is, in general, not difficult to find--that of a negative or prejudicial character is not sought. Then with a mind unconsciously biassed in favour of a preconceived idea, it may happen that probabilities are mistaken for facts, evidence for proof: and thus a new hypothesis is duly launched, based on ten, fifty, or a hundred adduced circumstances, the whole of which may be merely coincidences, and exceptions to the rule if applied to the millions of unadduced cases, and perhaps, even in relation to the particular examples cited, of no direct bearing in the sense in which it is sought to apply them.

As an example of the class of theories alluded to, we have read that the colours of the sea-gull tribe are dark above and light below in order, on the one hand, that they may escape the searching scrutiny of the eagle soaring above, and, on the other, avoid alarming their finny prey beneath. If there was anything in this idea, it would, at least, be a hard case for those sea-birds not so coloured, and it should be added that of the birds which are so coloured several species take three or four years to attain adult dress. How do they survive those earlier years? But a very slight acquaintance with the subjects in life shows that there is actually nothing in it. Lying in one's gunning-punt, the whitest-breasted gulls, as viewed from below against the lightest of cloud backgrounds, are seen as clearly as if the bird's colour was actually black. Every detail of form and movement is clearly distinguishable--the clean-cut wings and tail, legs pressed close up under the latter, the pointed head turning from side to side as it searches the waters. Its colour makes no difference, and is no factor at all. Then from high above, from the heights of a sea-cliff, what man of even moderate vision cannot distinguish with equal ease the movements of the black-backed gull from those of the pale herring-gull and paler tern? And both eagles and surface-swimming fish are infinitely keener of vision than the sharpest-eyed of our kind.

These remarks are penned from no love of argument, nor inspired by invidious motive, but simply with a view to get at _facts_ and thereby advance the interests of science: that is, of true knowledge.