The story of how islands are formed and inhabited went through many versions before Carson was satisfied. Her research on island evolution was aided by F. Raymond Fosberg, a tropical botanist at George Washington University and the Smithsonian’s National Museum, and a world expert on atoll formation. Fosberg read an early draft of Carson’s chapter which he later described as “the finest account of the creation and colonization of an oceanic island” he had ever read.
This version, titled “Lost Worlds,” was published in the magazine of the D.C. Audubon Society, The Wood Thrush, edited by Carson’s friend Shirley Briggs, in the spring of 1949. It is distinguished by Carson’s undisguised anger at the human destruction of the rare ecology of island habitats, her advocacy of island ecosystem preservation, and her delight in the mysterious processes of species migration to distant Atlantic atolls. Although a later version published in the Yale Review was awarded the Westinghouse Science Writing Prize from the American Association for the Advancement of Science, “Lost Worlds” brought Carson favorable notice from the small but influential Washington, D.C., science community whose support was crucial to her expanding literary career.
DR. ERNST MAYR of the American Museum of Natural History recently compiled a list of all species of birds known to have become extinct anywhere in the world during the past two centuries. This was his score: on all continents combined, eight species; on islands, at least ninety-two – probably more than a hundred when all reports from war areas are in.
This report epitomizes the tragedy of island life that is playing out what may well be its last act before our eyes. Each of the ninety-two species named by Dr. Mayr represents a loss that will never be replaced. For most of these island species have been created once, and only once, in all the world, the products of the slow processes of the ages. Destroyed by man’s careless abuse of the most delicately balanced environment in the world, an oceanic island, they are lost forever.
The problem of the islands is not one that can be put off until later; it is not one that will solve itself if we adopt a comfortable policy of laissez faire. Our own generation is in all probability the last that will have an opportunity to save any of the original island faunas and floras. The Atlantic islands, whose discovery and colonization began back in the sixteenth century, were despoiled so long ago that we scarcely realize what was lost. The islands of the Indian Ocean and parts of the Pacific came in for their turn a little later. The immense distances of the vast Pacific, the remoteness of many of its islands from the routes of whalers and traders, for a time saved some of the Pacific islands, but not for long. Today there are in all the world only a few islands whose original life remains.
Islands present a conservation problem that is absolutely unique, a fact that is not generally realized. This uniqueness stems from the nature of the island species, and from the delicately balanced relationships between island animals and plants and their environment. And going back still farther, these things are related to the origin of the islands themselves, and to the amazing manner in which they acquired their faunas and floras.
The islands of the deep ocean, far from the continents, are the products of an extraordinary process of earth-building. With few exceptions, they are the result of the violent, explosive, earth-shaking eruptions of submarine volcanoes, working perhaps for thousands or millions of years. In eruption after eruption the mass of an undersea mountain takes form on the floor of the ocean, builds up toward the surface, emerges as an island.
On their first emergence from the sea, these islands are bare, harsh, and repelling beyond human experience. No living creature moves over their volcanic hills; no plants cover their naked lava fields. By what miracle are these islands, isolated by hundreds or thousands of miles from other land, transformed into forested hills and fertile valleys, bright with birds and stirring with life?
The stocking of the islands has been accomplished by the strangest migration in earth’s history – a migration that began long before man appeared on earth and must still be continuing, a migration that seems more like a series of cosmic accidents than an orderly process of nature. Little by little, riding on the winds, drifting on the currents, or rafting in on logs, floating brush, or trees, the plants and animals that are to colonize them arrive from the distant continents.
So deliberate, so unhurried, so inexorable are the ways of Nature that the stocking of an island may require thousands or millions of years. It may be that no more than half a dozen times in all these eons does a particular form, such as a tortoise, make a successful landing upon its shores. To wonder impatiently why man is not a constant witness of such arrivals is to fail to understand the majestic pace of the process.
Yet we have occasional glimpses of the method. Natural rafts of uprooted trees and matted vegetation have frequently been seen adrift at sea, hundreds of miles off the mouths of such great tropical rivers as the Congo, the Ganges, the Amazon, and the Orinoco. Such rafts could easily carry an assortment of insect, reptile, or mollusk passengers. Some of these involuntary passengers might be able to withstand long weeks at sea; others would die during the first stages of the journey. Probably the best adapted for travel by raft are the wood-boring insects, which, of all the insect tribe, are most commonly found on oceanic islands. The poorest raft travelers must be the mammals, yet even a mammal might cover short inter-island distances.
No less than the water, the winds and the air currents play their part in bringing inhabitants to the islands. With special nets and traps, scientists have now collected from the upper atmosphere many of the forms which inhabit oceanic islands. Spiders, whose almost invariable presence on these islands is an intriguing problem, have been captured nearly three miles above the earth’s surface. Airmen have passed through great numbers of the white, silken filaments of spiders’ “parachutes” at heights of two to three miles. At altitudes of 6,000 to 16,000 feet, and with wind velocities reaching 45 miles an hour, many living insects have been taken. At such heights and on such strong winds, they might well have been carried hundreds of miles. Seeds have been collected at altitudes up to 5,000 feet. Among those commonly taken are members of the Composite family, typical of oceanic islands.
The wide-ranging birds that visit islands of the ocean in migration may also have a good deal to do with the distribution of plants, and perhaps even of some insects and minute land shells. From a ball of mud taken from a bird, Charles Darwin raised eighty-two separate plants, belonging to five distinct species! Many plant seeds have hooks or prickles, ideal for attachment to feathers. Such birds as the Pacific Golden Plover, which annually flies from the mainland of Alaska to the Hawaiian Islands and even beyond, probably figure in many riddles of plant distribution.
Isolated from the great mass of life on the continents, with no opportunity for the cross-breeding which tends to preserve the average, to eliminate the new and unusual, island life has developed in a remarkable manner. On these remote bits of earth, Nature has excelled in the creation of strange and wonderful forms. As though to prove her incredible versatility, almost every island has developed species which are endemic; that is, they are peculiar to it alone, and are duplicated nowhere else on earth.
The strange plants and animals of the Galapagos Islands – giant tortoises, black, amazing lizards that hunted their food in the surf, birds in extraordinary variety – moved Charles Darwin, years after his visit to the islands, to write in reminiscence: “Both in space and time we seem to be brought somewhat near to that great fact – that mystery of mysteries – the first appearance of new beings on earth.”
Of the “new beings” evolved on islands, some of the most striking examples have been birds. In some remote age before there were men, a small, pigeon-like bird found its way to the island of Mauritius, in the Indian Ocean. By processes of change at which we can only guess, this bird lost its power of flight, developed short, stout legs, grew larger until it reached the size of a modern turkey. Such was the origin of the fabulous Dodo
, which did not long survive the advent of man on Mauritius. New Zealand was the sole home of the Moa, an ostrich-like bird that stood twelve feet high. Moas had roamed New Zealand from the time of the Pliocene, but they died out soon after the arrival of the Maoris.
Besides the Dodo and the Moa, other island forms have tended to become large. The loss of wing use and even of the wings themselves (the Moa had none) is a common result of insular life. Insects on small, wind-swept islands lose the power of flight. The Galapagos Islands have a flightless cormorant. There have been at least fourteen species of flightless rails in the islands of the Pacific alone.
One of the most interesting and engaging characteristics of island species is their extraordinary tameness, a lack of sophistication in dealings with the human race which even the bitter teachings of experience do not quickly alter. When Robert Cushman Murphy visited the island of South Trinidad in 1913 with a party from the brig Daisy, terns alighted on the heads of the men in the whaleboat and peered inquiringly into their faces. Albatrosses on Laysan, whose habits include wonderful ceremonial dances, allowed naturalists to walk among their colonies, and responded with a grave bow to similar polite greetings from the visitors. When the British ornithologist David Lack visited the Galapagos Islands, a century after Darwin, he found that the hawks allowed themselves to be touched, and the flycatchers tried to remove hair from the heads of the men for nesting material. “It is a curious pleasure,” he wrote, “to have the birds of the wilderness settling upon one’s shoulders, and the pleasure could be much less rare were man less destructive.”
But man, unhappily, has written one of his blackest records as a destroyer on the oceanic islands. He has seldom set foot on an island that he has not brought about disastrous changes. He has destroyed environments by cutting, clearing, and burning; he has brought with him as a chance associate the nefarious rat; and almost invariably he has turned loose upon the islands a whole Noah’s Ark of goats, hogs, cattle, dogs, cats, and other non-native animals and plants. Upon species after species of island life, the night of extinction has fallen.
In the world of living things, it is doubtful whether there is a more delicately balanced relationship than that of island life to its environment. In the midst of a great ocean, ruled by currents and winds that rarely shift their course, climate changes little. There are few natural enemies, perhaps none. The harsh struggle for existence that is the normal lot of continental life is softened on the islands. When this gentle pattern of life is abruptly changed, the island creatures have little ability to make the adjustments necessary to survival.
Ernst Mayr tells of a steamer wrecked off Lord Howe Island east of Australia in 1918. Its rats swam ashore. In two years they had so nearly exterminated the native birds that an islander wrote: “This paradise of birds has become a wilderness, and the quietness of death reigns where all was melody.”
On Tristan da Cunha, all of the unique land birds that had been evolved there in the course of the ages were exterminated by the hogs and the rats. The native fauna of Tahiti and thousands of other Pacific islands is losing ground against the horde of alien species that man has introduced.
Most of man’s habitual tampering with Nature’s balance by introducing exotic species has been done in ignorance of the fatal chain of events that would follow. But in modern times, at least, we might profit by history. About the year 1513, the Portuguese introduced goats onto the recently discovered island of St. Helena, which had developed a magnificent forest of gumwood, ebony, and brazilwood. By 1560 or thereabouts, the goats had so multiplied that they wandered over the island by the thousand, in flocks a mile long. They trampled the young trees and ate the seedlings. By this time the colonists had begun to cut and burn the forests, so that it is hard to say whether men or goats were the more responsible for their destruction. But of the result there was no doubt. Even as early as the year 1880 the naturalist Alfred Wallace had to describe this once beautiful, forest-clad volcanic island as a “rocky desert,” in which the fugitive remains of the original flora persisted only in the most inaccessible peaks and craters.
When the astronomer Halley visited the islands of the Atlantic about 1700, he put a few goats ashore on South Trinidad. This time without the further aid of man, the work of destruction proceeded so rapidly as to be nearly completed within the century. Today Trinidad’s slopes are the place of a ghost forest, strewn with the fallen and decaying trunks of long-dead trees; its soft volcanic soils, no longer held by the interlacing roots, are sliding away into the sea.
The Hawaiian Islands, which have lost their native plants and animals faster than almost any other area in the world, are a classic example of the results of interfering with natural balances. Certain relationships of animal to plant, and of plant to soil, had grown up through the centuries. When man came in and rudely disturbed this balance, he set off a whole series of chain reactions.
Vancouver brought cattle and goats to the Hawaiian Islands, and the resulting damage to forests and other vegetation was enormous. Many plant introductions were as bad. A plant known as the pamakani was brought in many years ago, according to report, by a Captain Makee for his beautiful gardens on the island of Maui. The pamakani, which has light, wind-borne seeds, quickly escaped from the Captain’s gardens, ruined the pasture lands on Maui, and proceeded to hop from island to island. The CCC boys once were put to work to clear it out of the Honouliuli Forest Reserve, but as fast as they destroyed it, the seeds of new plants arrived on the wind. Lantana was another plant brought in as an ornamental species. Now it covers thousands of acres with a thorny, scrambling growth – despite large sums of money spent to import parasitic insects to control it.
There was once a society in Hawaii for the special purpose of introducing exotic birds. Today when you go to the islands, you see, instead of the exquisite native birds that greeted Captain Cook, mynahs from India, cardinals from the United States or Brazil, skylarks from Europe, and titmice from Japan. Most of the original bird life has been wiped out, and to find its fugitive remnants you would have to search assiduously in the most remote hills.
One of the most interesting of the Pacific islands was Laysan, one of the far outriders of the Hawaiian chain, a tiny scrap of volcanic soil. It once supported a forest of sandalwood and fan-leaf palms, and had five land birds, all peculiar to Laysan alone. One of them was the Laysan Rail, a charming, gnome-like creature no more than six inches high, with wings that seemed too small (and were never used as wings) and feet that seemed too large, and a voice like tinkling bells. About 1887, the captain of a visiting ship moved some of the Rails to Midway, establishing a second colony. This seemed a fortunate move, for soon thereafter rabbits were introduced on Laysan. Within a quarter of a century the rabbits had killed off the vegetation of the tiny island, reduced it to a sandy desert, and all but exterminated themselves. As for the Rails, the devastation of their island was fatal, and the last Rail on Laysan died about 1924.
Perhaps the Laysan colony could later have been restored from the Midway group had not tragedy struck there also. During the war in the Pacific, rats went ashore from ships and landing craft on island after island. They invaded Midway in 1943. The adult Rails were slaughtered. The eggs were eaten, and the young birds killed. The world’s last Laysan Rail was seen in 1944.
The disruptive forces that had been operating for centuries throughout the Pacific were greatly accelerated by war. Some of the destruction was the direct result of bombing and artillery fire, but much of it was indirect. Ulithi Atoll in the Carolines was the home of a small rail, found nowhere else. The rail survived the early period of invasion, but perished when the taro swamps in which it lived were filled to make way for quonset huts. Large birds like albatrosses, shearwaters, and petrels often fell into abandoned foxholes and other steep-sided pits from which they could not escape, and starved. Planes killed thousands of birds, especially kinds that are active at night, like the Sooty Terns.
Out of the Pacific war, however
, grew the first recognition of the conservation problem of the islands, and the first small beginnings of a constructive movement to salvage what remains. In 1946, the Pacific War Memorial was established. One of its purposes is the commemoration of lives lost in the Pacific by preserving, as living memorials, examples of original island life. Late in 1948 the Pacific War Memorial established a laboratory on the island of Koror, in the Palau Archipelago, to begin a study of conservation problems. The conservation crisis in the Pacific islands has also been the subject of several conferences sponsored by the National Research Council’s Pacific Science Board. The advice of leading specialists on Pacific conservation problems has been sought by the Navy in connection with the Trust Territory of Micronesia.
There is still a chance to preserve some of the unique island life of the Pacific by establishing sanctuary areas comparable to our own National Parks and Wildlife Refuges. The first actual start on such a program has just been made. Late in 1948, the Navy turned over to the Pacific War Memorial two areas on Saipan as conservation reserves to commemorate the men who died in the fighting on this island. Between them, the two areas – Lake Susupe and Mt. Tapotchau – contain almost the only remaining vestiges of the original wildlife and forests of the island.
Lake Susupe, with its surrounding swamp, is the last stronghold in the world of one of Micronesia’s most interesting birds, the Marianas Mallard. This bird has always been rare, and museums anywhere in the world that had a specimen counted themselves lucky. It was first described by scientists less than a century ago, from a single specimen in the Paris museum. It was found only on Guam, Tinian, and Saipan, and even there flocks of more than fifty or sixty birds were an unusual sight. It now seems to have disappeared from both Tinian and Guam, and probably not more than a score remain on Saipan. Under protection on Lake Susupe, conservationists hope that this remnant may build up enough to save the species from extinction.*