Swoosh-swoosh-slap. It sounds like an injured bird, beating its wings against the door of my room. This would not surprise me. The coral caye of Heron Island is alive with birds. Friendly black noddy terns perch on virtually every branch, the tang of ammonia hangs in the hot air, and the ground is riddled with the burrows of mutton birds, who serenade each other with ghostly "wooh woohs".
But when I check, there is no bird. The flapping-slapping sound is rising from the sand directly below my balcony. I look out and smell wet sand. Below me, a turtle the size of a coffee table is sweeping great flipperfuls of sand into the air as she digs a pit in which to lay her eggs. Right there, in the moonlight, this enormous prehistoric beast looks like an alien cocoon fallen to earth, in her own crater of sand. She pauses, and I wonder if she has seen me, but she is in a trance. And then she starts digging again, flicking sand behind her with her formidable front flippers.
It is impossible to land on a tiny tropical island and not break into a smile. Just 800m long and 300m wide, Heron Island lies 45 miles off the coast of Queensland, at the southern end of the Great Barrier Reef. While Queensland has become synonymous with floods and cyclones in the past year, the vast majority of this huge state has been unaffected, and even affected areas soon got back to normal.
I visited Heron in the December- March cyclone season and enjoyed idyllic sunny days, with soft sea breezes keeping the humidity down at night. Fringed by octopus bushes – so named because their seeds look like octopus tentacles – and by the weeping grey needles of the coastal she-oak, the white sand and turquoise water was an entrance into a tropical paradise.
Close to the tropic of Capricorn, the sands of Heron were blown into an island 6,000 years ago. And this fragile new landscape didn't develop into an authentic coral caye, with its reservoir of fresh water above the reef, until about 1,500 years ago. Seeds were carried over by wind, waves and in bird droppings, and now the island boasts dense woodland and a profusion of bird life including 70,000 black noddy terns and 30,000 mutton birds. (Heron is a misnomer: the island was named by a geologist who mistook the egrets for herons.)
Apart from the occasional boat-hopping house mouse (these are eradicated as soon as possible), the only mammals on Heron are humans. Over the years, they have had a fairly gruesome impact. Thousands of green turtles have always visited Heron's beaches between November and March to lay their eggs, and the first use Western settlers made of the island was to set up a canning factory for turtle soup in the 1920s.
This folded when the turtle population, predictably, crashed and in the 1930s Heron became a tourist resort. It was given national park status in the 1940s, and a scientific research station was added in the 1950s. World Heritage status as part of the Great Barrier Reef now enforces stringent environmental protection.
While some people visit Heron for whale watching, to dive and snorkel, or just to chill out on a tropical beach, this tiny blob of paradise is for most all about the turtles. Within minutes of arriving, I am running across the empty beach, the white sand of crushed up coral coarse beneath my feet. Up close, the sand is speckled with tiny red grains from the bright organ pipe coral. As I float in the shallow reef water, alongside a couple of harmless but still menacingly finned reef sharks, three other holidaymakers arrive carrying a handful of baby turtles – hatchlings – that unwisely chose to emerge during the day, rather than under cover of darkness.
The black hatchlings, tiny enough to fit in your palm, are placed in the water and, like clockwork toys, flap, leap and speed away. Instantly, silver gulls swoop in. The hatchlings are just too easy to spot in the clear water, and whenever they surface to breathe, the gulls snatch them up. I join in the rescue effort, splashing and shouting at the gulls. We distract them enough to allow just one hatchling to swim out to sea. Most don't make it.
I have better luck with another rescue effort, when Tim Harvey, director of the Sea Turtle Foundation, goes to the aid of a stranded turtle. Tim, a passionate mine of turtle information, gives fascinating lectures, and often joins early morning and late evening expeditions to see the turtles laying their eggs.
Harvey has spotted a large turtle, its mottled grey-green shell looking just like an algae-covered boulder, stranded on the beach. This female laid eggs but the retreating tide led her into a rock cul-de-sac. Not possessing a reverse gear, she was trapped. In the midday sun, she would soon cook in her shell and die, boiled alive. With four helpers to lift her 180kg body, Harvey soon hauls her from her rocky prison until she can heave herself clumsily towards the water. As soon as she reaches the shallows, a great transformation takes place: she goes from awkward to graceful in seconds, accelerating into the ocean as if taking off. "Turtles don't swim," sighs Tim. "They fly."
Visitor numbers are limited to 300 in the resort, and with staff and more than 100 biologists working at the research station at peak times, the island is often well-populated by humans. But it does not feel crowded, and I am always able to find an empty stretch of beach or forest glade. For lovers of even quieter tropical islands, Wilson Island nearby allows only 12 guests at a time.
"Even when we're flat out you can walk around this island and wonder where everybody is," says Tim. "Sometimes I despair about the environment – after 40 years of campaigning to save the rainforest we're cutting it down more quickly than ever – but here we manage to coexist not too badly with the wildlife. I'm sure we do have an impact, but this would be a really good place for a study of how humans and animals could coexist."
Heron Island's resort is meticulous about ensuring the turtles are not disturbed by guests, who stay in spacious en suite apartments, with balconies and sea views, and dine in an excellent restaurant. Staff are knowledgeable about the turtles, and regulations ensure we do not disturb the wildlife: even when mutton bird nests pop up in the middle of pathways they are protected. I am shocked, however, that while the resort has solar-powered hot water, it relies on diesel generators for electricity. The manager tells me this is because strict rules protecting trees mean many roofs are shaded, but I can see plenty of exposed roof space crying out for panels. I hope it invests in solar soon.
There is fine diving off Heron, and as I wait at the jetty for a boat to take me to the reef's edge, a white-spotted eagle ray the size of a dinner table leaps out of the water and belly-flops back dramatically in an attempt to shake off the fish sucking on to its underside. With just a snorkel I gain entrance into a parallel universe, a mosaic of coral in subtle shades of orange, brown and pale blue. Others in the group spot turtles and a fleet of rays, looking like alien spaceships, while I admire a trumpet fish – a long thin tube that moves silently and cautiously through the water – and parrotfish in yellow and turquoise who dash this way and that, flapping their fins like fussy birds, shooing other fish off the reef.
As a gloriously mosquito-free night falls, (mosquitoes are rare on Heron) we head to the beach to watch turtles. Six of the world's seven turtle species are found in northern Queensland, from the enormous leatherbacks to fearless loggerheads. On Heron, the main species are green turtles. In a good year, 150 haul themselves on to the beach to lay eggs each night. Last year there were only about 30 each night but this is cyclical; this year there has been an average of 80.
Great tracks up the sand reveal the route of laying turtles. Beyond the high-tide line we can hear sounds of digging before we see their great shells in the half-light. Visitors are given careful guidelines about how to watch turtles – not to shine bright torches on them, not to cross a turtle's path or stand in front of one – but it is surprising how close you can get without disturbing them. They go into a nesting trance when they lay, and cannot see you when you stand behind them, though their acute sense of vibrations in the sand means you still have to tread carefully.
We sit on the cool sand and watch a turtle laying her eggs. She takes her time, first crashing around digging a pit with her strong front flippers, and then digging much more precisely with her rear flippers, which are as clever as hands, to create a little chamber for her eggs. Then, one by one, her ping-pong ball eggs plop out, soft and bouncy as they hit the sand. During the November-February laying season, females will lay a nest of 120 eggs, go away for a fortnight, then return to lay another, repeating this perhaps five times. The eggs take 55 days to hatch.
Leaving her in peace, we head along the beach to find an "eruption" – a nest that has hatched. Hatchlings are "guaranteed to leave you completely wobbly-legged", says Tim. Turtles have a high hatch rate on Heron because there are no feral pigs or dogs to dig up the eggs, only the rather sinister ghost crabs, which puncture the eggs to suck out the yolk. The hatchlings march down the beach towards the water in a great phalanx. Even at night, gulls pick off dozens. The hatchlings' only protection is sheer numbers. I spot a scurrying ghost crab, and chase it with my torch. It appears to shed a skin and dash on. Looking closer, I see its "skin" is a snatched, headless baby turtle. Another one down.
At dawn, we catch the last of the turtles finishing their laying. I watch one lumber towards the ocean. She looks a bit silly at first, with sand all over her face from her Herculean digging. Then she turns her face, with her funny little nostrils, and one oval black eye rests on us. Now I'm the silly one. Like any powerful encounter with nature, the gaze of a turtle is humbling. It makes us feel small, as if this ancient species is quietly questioning all the environmental degradation we have visited upon its world. Then she takes off, majestically, flying into the turquoise water.
