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.