It was quite otherwise with the unobtrusive small deer of life—the snails, and beetles, and flies, and earthworms—and especially with the winged things: birds, bats, and butterflies. In the very earliest days of my islands' existence, indeed, a few stray feathered fowls of the air were driven ashore here by violent storms, at a time when vegetation had not yet begun to clothe the naked pumice and volcanic rock; but these, of course, perished for want of food, as did also a few later arrivals, who came under stress of weather at the period when only ferns, lichens, and mosses had as yet obtained a foothold on the young archipelago. Sea-birds, of course, soon found out our rocks; but as they live off fish only, they contributed little more than rich beds of guano to the permanent colonising of the islands. As well as I can remember, the land-snails were the earliest truly terrestrial casuals that managed to pick up a stray livelihood in these first colonial days of the archipelago. They came oftenest in the egg, sometimes clinging to water-logged leaves cast up by storms, sometimes hidden in the bark of floating driftwood, and sometimes swimming free on the open ocean. In one case, as I recall to myself well, a swallow, driven off from the Portuguese coast, a little before the Glacial period had begun to whiten the distant mountains of central and northern Europe, fell exhausted at last upon the shore of Terceira. There were no insects then for the poor bird to feed upon, so it died of starvation and weariness before the day was out; but a little earth that clung in a pellet to one of its feet contained the egg of a land-shell, while the prickly seed of a common Spanish plant was entangled among the winged feathers by its hooked awns. The egg hatched out, and became the parent of a large brood of minute snails, which, outliving the cold spell of the Ice Age, had developed into a very distinct type in the long period that intervened before the advent of man in the islands; while the seed sprang up on the natural manure heap afforded by the swallow's decaying body, and clinging to the valleys during the Glacial Age on the hill-tops, gave birth in due season to one of the most markedly indigenous of our Terceira plants.

Occasionally, too, very minute land-snails would arrive alive on the island after their long sea-voyage on bits of broken forest-trees—a circumstance which I would perhaps hesitate to mention in mere human society were it not that I have been credibly informed your own great naturalist, Darwin, tried the experiment himself with one of the biggest European land-molluscs, the great edible Roman snail, and found that it still lived on in vigorous style after immersion in sea-water for twenty days. Now, I myself observed that several of these bits of broken trees, torn down by floods in heavy storm time from the banks of Spanish or Portuguese rivers, reached my island in eight or ten days after leaving the mainland, and sometimes contained eggs of small land-snails. But as very long periods often passed without a single new species being introduced into the group, any kind that once managed to establish itself on any of the islands usually remained for ages undisturbed by new arrivals, and so had plenty of opportunity to adapt itself perfectly by natural selection to the new conditions. The consequence was, that out of some seventy land-snails now known in the islands, thirty-two had assumed distinct specific features before the advent of man, while thirty-seven (many of which, I think, I never noticed till the introduction of cultivated plants) are common to my group with Europe or with the other Atlantic islands. Most of these, I believe, came in with man and his disconcerting agriculture.

As to the pond and river snails, so far as I could observe, they mostly reached us later, being conveyed in the egg on the feet of stray waders or water-birds, which gradually peopled the island after the Glacial epoch.

Birds and all other flying creatures are now very abundant in all the islands; but I could tell you some curious and interesting facts, too, as to the mode of their arrival and the vicissitudes of their settlement. For example, during the age of the Forest Beds in Europe, a stray bullfinch was driven out to sea by a violent storm, and perched at last on a bush at Fayal. I wondered at first whether he would effect a settlement. But at that time no seeds or fruits fit for bullfinches to eat existed on the islands. Still, as it turned out, this particular bullfinch happened to have in his crop several undigested seeds of European plants exactly suited to the bullfinch taste; so when he died on the spot, these seeds, germinating abundantly, gave rise to a whole valleyful of appropriate plants for bullfinches to feed upon. Now, however, there was no bullfinch to eat them. For a long time, indeed, no other bullfinches arrived at my archipelago. Once, to be sure, a few hundred years later, a single cock bird did reach the island alone, much exhausted with his journey, and managed to pick up a living for himself off the seeds introduced by his unhappy predecessor. But as he had no mate, he died at last, as your lawyers would say, without issue.

It was a couple of hundred years or so more before I saw a third bullfinch—which didn't surprise me, for bullfinches are very woodland birds, and non-migratory into the bargain—so that they didn't often get blown seaward over the broad Atlantic. At the end of that time, however, I observed one morning a pair of finches, after a heavy storm, drying their poor battered wings upon a shrub in one of the islands. From this solitary pair a new race sprang up, which developed after a time, as I imagined they must, into a distinct species. These local bullfinches now form the only birds peculiar to the islands; and the reason is one well divined by one of your own great naturalists (to whom I mean before I end to make the amende honorable). In almost all other cases the birds kept getting reinforced from time to time by others of their kind blown out to sea accidentally—for only such species were likely to arrive there—and this kept up the purity of the original race, by ensuring a cross every now and again with the European community. But the bullfinches, being the merest casuals, never again to my knowledge were reinforced from the mainland, and so they have produced at last a special island type, exactly adapted to the peculiarities of their new habitat.

You see, there was hardly ever a big storm on land that didn't bring at least one or two new birds of some sort or other to the islands. Naturally, too, the newcomers landed always on the first shore they could sight; and so at the present day the greatest number of species is found on the two easternmost islands nearest the mainland, which have forty kinds of land-birds, while the central islands have but thirty-six, and the western only twenty-nine. It would have been quite different, of course, if the birds came mainly from America with the trade winds and the Gulf Stream, as I at first anticipated. In that case, there would have been most kinds in the westernmost islands, and fewest stragglers in the far eastern. But your own naturalists have rightly seen that the existing distribution necessarily implies the opposite explanation.

Birds, I early noticed, are always great carriers of fruit-seeds, because they eat the berries, but don't digest the hard little stones within. It was in that way, I fancy, that the Portugal laurel first came to my islands, because it has an edible fruit with a very hard seed; and the same reason must account for the presence of the myrtle, with its small blue berry; the laurustinus with its currant-like fruit; the elder-tree, the canary laurel, the local sweet-gale, and the peculiar juniper. Before these shrubs were introduced thus unconsciously by our feathered guests, there were no fruits on which berry-eating birds could live; but now they are the only native trees or large bushes on the islands—I mean the only ones not directly planted by you mischief-making men, who have entirely spoilt my nice little experiment.

It was much the same with the history of some among the birds themselves. Not a few birds of prey, for example, were driven to my little archipelago by stress of weather in its very early days; but they all perished for want of sufficient small quarry to make a living out of. As soon, however, as the islands had got well stocked with robins, black-caps, wrens, and wagtails, of European types—as soon as the chaffinches had established themselves on the seaward plains, and the canary had learnt to nest without fear among the Portugal laurels—then buzzards, long-eared owls, and common barn-owls, driven westward by tempests, began to pick up a decent living on all the islands, and have ever since been permanent residents, to the immense terror and discomfort of our smaller song-birds. Thus the older the archipelago got the less chance was there of local variation taking place to any large degree, because the balance of life each day grew more closely to resemble that which each species had left behind it in its native European or African mainland.

I said a little while ago we had no mammal in the islands. In that I was not quite strictly correct. I ought to have said, no terrestrial mammal. A little Spanish bat got blown to us once by a rough nor'easter, and took up its abode at once among the caves of our archipelago, where it hawks to this day after our flies and beetles. This seemed to me to show very conspicuously the advantage which winged animals have in the matter of cosmopolitan dispersion; for while it was quite impossible for rats, mice, or squirrels to cross the intervening belt of three hundred leagues of sea, their little winged relation, the flitter-mouse, made the journey across quite safely on his own leathery vans, and with no greater difficulty than a swallow or a wood-pigeon.

The insects of my archipelago tell very much the same story as the birds and the plants. Here, too, winged species have stood at a great advantage. To be sure, the earliest butterflies and bees that arrived in the fern-clad period were starved for want of honey; but as soon as the valleys began to be thickly tangled with composites, harebells, and sweet-scented myrtle bushes, these nectar-eating insects established themselves successfully, and kept their breed true by occasional crosses with fresh arrivals blown to sea afterwards. The development of the beetles I watched with far greater interest, as they assumed fresh forms much more rapidly under their new conditions of restricted food and limited enemies. Many kinds I observed which came originally from Europe, sometimes in the larval state, sometimes in the egg, and sometimes flying as full-grown insects before the blast of the angry tempest. Several of these changed their features rapidly after their arrival in the islands, producing at first divergent varieties, and finally, by dint of selection, acting in various ways, through climate, food, or enemies, on these nascent forms, evolving into stable and well-adapted species. But I noticed three cases where bits of driftwood thrown up from South America on the western coasts contained the eggs or larvae of American beetles, while several others were driven ashore from the Canaries or Madeira; and in one instance even a small insect, belonging to a type now confined to Madagascar, found its way safely by sea to this remote spot, where, being a female with eggs, it succeeded in establishing a flourishing colony. I believe, however, that at the time of its arrival it still existed on the African continent, but becoming extinct there under stress of competition with higher forms, it now survives only in these two widely separated insular areas.

It was an endless amusement to me during those long centuries, while I devoted myself entirely to the task of watching my fauna and flora develop itself, to look out from day to day for any chance arrival by wind or waves, and to follow the course of its subsequent vicissitudes and evolution. In a great many cases, especially at first, the new-comer found no niche ready for it in the established order of things on the islands, and was fain at last, after a hard struggle, to retire for ever from the unequal contest. But often enough, too, he made a gallant fight for it, and, adapting himself rapidly to his new environment, changed his form and habits with surprising facility. For natural selection, I found, is a hard schoolmaster. If you happen to fit your place in the world, you live and thrive, but if you don't happen to fit it, to the wall with you without quarter. Thus sometimes I would see a small canary beetle quickly take to new food and new modes of life on my islands under my very eyes, so that in a century or so I judged him myself worthy of the distinction of a separate species; while in another case, I remember, a south European weevil evolved before long into something so wholly different from his former self that a systematic entomologist would have been forced to enrol him in a distinct genus. I often wish now that I had kept a regular collection of all the intermediate forms, to present as an illustrative series to one of your human museums; but in those days, of course, we none of us imagined anybody but ourselves would ever take an interest in these problems of the development of life, and we let the chance slide till it was too late to recover it.

Naturally, during all these ages changes of other sorts were going on in my islands—elevations and subsidences, separations and reunions, which helped to modify the life of the group considerably. Indeed, volcanic action was constantly at work altering the shapes and sizes of the different rocky mountain-tops, and bringing now one, now another, into closer relations than before with its neighbours. Why, as recently as 1811 (a date which is so fresh in my memory that I could hardly forget it) a new island was suddenly formed by submarine eruption off the coast of St. Michael's, to which the name of Sabrina was momentarily given by your human geographers. It was about a mile around and 300 feet high; but, consisting as it did of loose cinders only, it was soon washed away by the force of the waves in that stormy region. I merely mention it here to show how recently volcanic changes have taken place in my islands, and how continuously the internal energy has been at work modifying and re-arranging them.

Up to the moment of the arrival of man in the archipelago the whole population, animal and vegetable, consisted entirely of these waifs and strays, blown out to sea from Europe or Africa, and modified more or less on the spot in accordance with the varying needs of their new home. But the advent of the obtrusive human species spoilt the game at once for an independent observer. Man immediately introduced oranges, bananas, sweet potatoes, grapes, plums, almonds, and many other trees or shrubs, in which, for selfish reasons, he was personally interested. At the same time he quite unconsciously and unintentionally stocked the islands with a fine vigorous crop of European weeds, so that the number of kinds of flowering plants included in the modern flora of my little archipelago exceeds, I think, by fully one-half that which I remember before the date of the Portuguese occupation. In the same way, besides his domestic animals, this spoil-sport colonist man brought in his train accidentally rabbits, weasels, mice, and rats, which now abound in many parts of the group, so that the islands have now in effect a wild mammalian fauna. What is more odd, a small lizard has also got about in the walls—not as you would imagine, a native-born Portuguese subject, but of a kind found only in Madeira and Teneriffe, and, as far as I could make out at the time, it seemed to me to come over with cuttings of Madeira vines for planting at St. Michael's. It was about the same time, I imagine, that eels and gold-fish first got loose from glass globes into the ponds and water-courses.

I have forgotten to mention, what you will no doubt yourself long since have inferred, that my archipelago is known among human beings in modern times as the Azores; and also that traces of all these curious facts of introduction and modification, which I have detailed here in their historical order, may still be detected by an acute observer and reasoner in the existing condition of the fauna and flora. Indeed, one of your own countrymen, Mr. Goodman, has collected all the most salient of these facts in his 'Natural History of the Azores,' and another of your distinguished men of science, Mr. Alfred Russel Wallace, has given essentially the same explanations beforehand as those which I have here ventured to lay, from another point of view, before a critical human audience. But while Mr. Wallace has arrived at them by a process of arguing backward from existing facts to prior causes and probable antecedents, it occurred to me, who had enjoyed such exceptional opportunities of watching the whole process unfold itself from the very beginning, that a strictly historical account of how I had seen it come about, step after step, might possess for some of you a greater direct interest than Mr. Wallace's inferential solution of the self-same problem. If, through lapse of memory or inattention to detail at so remote a period, I have set down aught amiss, I sincerely trust you will be kind enough to forgive me. But this little epic of the peopling of a single oceanic archipelago by casual strays, which I alone have had the good fortune to follow through all its episodes, seemed to me too unique and valuable a chapter in the annals of life to be withheld entirely from the scientific world of your eager, ephemeral, nineteenth century humanity.