For islands that had such an apocalyptic volcanic birth, they are strangely silent much of the time. The absence of any large mammals in the Galapagos means that the braying cacophony of life is confined to the clamour of nesting seabirds and the occasional hiss of a reptile. For the latter they are, of course, the feature for which the islands have become globally renowned, with the world’s only true marine lizard munching algae beneath rolling Pacific swells, and giant tortoises moving regally from place to place on great wrinkled cantilevers that speak more of Brunel than Bellamy.

But to really know these islands, one must take to the sea. Not for nothing were they known as the Islas Encantadas by the first sailing pioneers, those who came to pillage and plunder in 1831, mining a seam of natural riches unmatched anywhere else on a curved blue horizon. Beset on all sides by five ocean currents, the islands seemed magical and sinister to those who first saw them – the whalers, the pirates, and the settlers. The cold water of the Humboldt Current meeting the tepid water of the southern equatorial current created mists that swirled over eddies of dizzying complexity. Islands would materialise out of the stygian gloom like volcanic chimeras, to seemingly vanish moments later as the vessels twisted and spun in back currents and danced in seething swells. The tiller would kick, the boom would swing, and the sails would shudder. “Islas Encantadas,” the sailors whispered, the Enchanted Isles, six hundred miles offshore, dark and forbidding, surely the result of wizardry and witchcraft.

Of course, today they retain the name, but for very different reasons. The Galapagos Islands were declared a World Heritage Site in 1978 – the first on the planet – an event that marked the beginning of a concerted attempt to right the wrongs of those who had gone before. It is said that man is the only species capable of blushing, and the only species that needs to, and the ravaged, scorched landscapes of the main islands were a legacy of the very worst excesses of the human species.

And no island was more devastated than Floreana, the location of the first human settlement. Sitting in the southern point of the archipelago, the island had precisely what was required to support human life – altitude (creating verdant forests cloaking volcanic slopes), freshwater, a natural harbour, and lots of tortoises. Within four years, up to the very moment a 26 year old naturalist from Shrewsbury called Charles Darwin first set foot on Floreana, the landscape had been utterly decimated.

Pigs, cows, goats, and rats had advanced inland in a great viral wave that had a scorched earth effect on the delicate ecosystems of the interior. The many thousands of Giant Floreana tortoises that had criss-crossed the landscape for millennia were on the brink of extinction. Indeed as young Darwin walked up the track from the harbour, he was struck by the hundreds of discarded tortoise shells alongside the route.

“Oh those,” said Nicholas Lawson, the deputy governor of the island, “do you know I can tell which island a tortoise comes from just by the shape of its shell?”. And with those words the greatest biological idea of them all – evolution – was planted in Darwin’s enquiring mind, and indeed when he published On the Origin of Species in 1859, he credited Lawson for the comment. A concept that changed the way we think of the natural world, of the great elemental forces that shape life, and indeed the way we think about ourselves was all born on that devastated scrap of land, on the smouldering ecological aftermath of man meeting a new environment and taking what he felt was his by divine right.

And so Floreana is important. But today more so than ever, because it has become the focus of a global effort to restore it to its natural state. There is an ongoing multi- national initiative to re-wild this rare jewel, to turn the clock back and – in doing so – perhaps salve our guilty environmental conscience. All of mankind’s creativity, energy, and terrible intent was required to destroy it, and is now being used to rebuild the ecosystem piece by piece. And part of that resolute armada was now bobbing quietly at anchor off the glowering cliffs of Gardner Rock, a few miles to the south east of the main island itself. “Pirata” was a beautiful ketch, with the high equatorial sun burnishing her white superstructure, and in turn causing those onboard to squint as they moved with purpose about her deck. Sailing is the perfect way to reach Gardner, a whispering approach beneath full canvas, as the Pacific mutters and rustles on the bow, the elements combining to deliver salvation. And for “Pirata” that meant trying to save one of the rarest birds on earth.

If the giant tortoise was the seed of the idea for evolution, the moment that saw it truly bloom was Darwin noting the difference between the long beaks of mockingbirds between the various islands. This goes against perceived wisdom (surely it was the finches, the legendary Darwin finches!), and gets mockingbird scientists very excited indeed. The truth of the matter was that the finches were simply a bloody mass of feathers when they were returned to England, a pointless bundle of little dead brown birds, whereas the mockingbirds – larger, more easily distinguished – were individually labelled. Here it was, proof that natural selection did indeed craft exquisite and nuanced differences between creatures, differences masterfully attuned to the world immediately around them.

But Gardner is not just a rock, it is an ark. For here, huddled in desperate isolation, are the last 300 Floreana mockingbirds on earth. Their ancestral kin had been shot, trapped, and bludgeoned to death, and recent generations deprived of habitat and home as their island had been ravaged. And so they had come to Gardner, the final citadel for their kind, a bastion on which they would see out their days.

On “Pirata” were a group of scientists who had been monitoring this population, knowing as they do that here is the well-head for a future when the mockingbirds could once again cackle and chirp in the cloud forests that coat the slopes of the volcano at Floreana’s heart. Here was a precious global resource, one that needed to be constantly monitored, nurtured, and protected. For when they are gone one more link in the entirely unique ecosystem of the island will be irreparably broken.

Part of the research team on this day was Tamsyn Halls. Tam was not a scientist, she was a filmmaker, and (far more significantly for her at this precise juncture) she was not a sailor. “Pirata” was a grand old lady, who had seen a thing or two in her time, and although she retained a certain distressed style it is not unreasonable to say that her days of luxurious travel were behind her. The heat has been stifling on the passage from the harbour at San Cristobel island – fifty miles of heaving swells and suffocating proximity in the crowded saloon. Tam – 5’2” and eight stone wet through – has eaten little and vomited much. She has slept hardly at all. By the time the anchor chain rattled out of the locker, she was dehydrated, ashen, and moderately enfeebled.