The beauty and birds of Heron Island

By Carolyn Barry 14 July 2015
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Home to a diverse array of marine species, which attracts tourists and researchers alike, remote Heron Island is one of the Great Barrier Reef’s tropical gems

The specK that is Heron Island is a welcome sight when it breaks the turquoise horizon of the Coral Sea. After surging through the choppy waters for almost two hours, I’m eager to head to shore. Rimmed by beaches and surrounded by the clear waters of the Great Barrier Reef, the coral cay is about 80km north-east of Gladstone and feels a world away from civilisation. At just 800m long and 300m wide, the 22ha isle is slightly smaller than Sydney’s Royal Botanic Gardens. It’s located on the western end of the Heron Reef, which is home to 60 per cent of fish species and 70 per cent of coral species found in the Great Barrier Reef. Its marine biodiversity is a source of pride, and during my stay at the Heron Island Resort, I’m told that filmmaker and conservationist Jacques Cousteau included the Heron Bommie on his list of the world’s top 10 dive sites.

Each morning, just off the jetty, you can spy shovel-nosed rays, cowtail rays and pink whiprays partially buried in the sandy shallows, as well as blacktip and whitetip reef sharks cruising the shore. In fact, you need to watch where you step or snorkel, lest you disturb a resting ray. Alternatively, wait till the 3m tide has receded to expose the reef, and take a guided walk. But of all the flora and fauna on the island, turtles are the species that draw visitors from far and wide. Thousands of green turtles and a smattering of loggerheads nest on Heron each year, some travelling 3000km and following their inbuilt compasses to its shores. “People say they’ll go for a nice evening walk,” says Heron’s naturalist and activities manager, Jason Killen. “I tell them they may have to set aside two to three hours because you have to give way to all the turtles.” Their numbers are linked to the La Niña/El Niño patterns, which affect the amounts of seagrass available for turtles to feed upon.

A big turtlenesting year is usually followed by a small one, says Jason. At the peak of a good season, which starts about November, more than 200 females will heave themselves up the beach to lay their eggs each night. A single female will typically lay 5–7 clutches of 120 eggs in a season, but may not lay again for several years. Since it’s still early in the season when I visit, I see about 6–8 turtles each night. In the light of the full moon we spot shadows moving parallel to the shore. The faster, wiggling ones are lemon sharks, which swim so close that their dorsal fins break out of the water; the slower, lurching shadows are the turtles,searching for the perfect spot to land. Several of their domes become visible as they head onto the beach. The moonlight makes the nervous females skittish – they’re sensitive to movement but not sound, Jason says, as we freeze in position. If you’re really still, the turtles just think you’re a log or rock, he adds. Despite us willing them on, more often than not they cautiously turn around and disappear back into the water.

If you’re dedicated to seeing the nesting process, you may be in for a late night, as the quickest turtles take about two hours. They are painfully slow on land and can spend half an hour dragging themselves up to dry sand. Green turtles move their front flippers ‘butterfly’ style, pushing along with both limbs at the same time. The loggerheads prefer ‘freestyle’, using one flipper at a time. This is the main way to tell them apart in the darkness.

Once a female has found her spot, she spends about an hour digging a body pit and then an egg chamber, up to 50cm deep. She may abandon this at any point if the quality of the sand isn’t right or she gets spooked. Once she begins laying, though, she’s committed and it’s at this time you can move in close and see the action. It’s hard not to be in awe of this intimate moment. One large female we see is an old hand, Jason says, so she’s relaxed as she lays her clutch with her back flippers parted enough for us to have a clear view. We hear her expel a little pushing breath, which signals the release of the next few eggs.

After about 15 minutes, she begins raking the sand in, kneading the spot over the eggs to push out any air pockets. She spends another half-hour covering the spot before returning to the sea. The process leaves an indelible mark on me. In the quiet dark of the beach, with the lapping water and light breeze, I ponder the immense effort it’s taken for this mother to advance her species, and with such low odds of success. In about 55 days, about 80 per cent of these eggs will produce a hatchling. But only one in every 1000 of these will likely make it to adulthood (AG 123).

HERON ISLAND was discovered in 1843 by European surveyors aboard HMS Fly. The ship’s resident geologist named the island after the plentiful herons he saw on its shores. Those herons were later declared by scientists to be eastern reef egrets, but the name stuck. There was little development on Heron until the 1920s, when a turtle soup cannery was established, but it was short-lived. During the 1930s, Captain Christian Poulsen started ferrying tourists there and in 1936 he opened the Heron Island Resort. In 1943, the island was gazetted a national park, and today the eastern half of the island remains protected as part of the Capricornia Cays National Park. Heron’s remoteness keeps daytrippers away; it is only the resort’s guests (no more than 200) and staff, as well as a small contingent of researchers, who share the island. And, of course, the birds. In a bumper summer season, the oasis attracts some 200,000 seabirds. In his almost eight years working on the island, Jason estimates he’s seen about 120 different species, but there are about 25 he commonly spots.

It’s impossible to escape the cacophony of the 70,000–120,000 black noddy terns that nest each spring in the pisonia trees. The smell of guano hangs heavy in the air, alleviated only by the sea breeze, but you quickly get used to the pong. HERON ISLAND’s biodiversity has made it an ideal place to study the marine environment, and the variety of species has long drawn scientists to the reef. The world-renowned research centre (AG 122) on the island’s south-west is run by the University of Queensland and does work on climate change, reef ecology and seabirds. The island is also held in high regard by Sir David Attenborough, who was on location at Heron during my visit, filming a series about climate change, due for release this year. He’s had a long association with this isolated oasis. “Heron Island is a very interesting place,” says David. “I first went to Heron Island some 40 years ago. It not only has a very good visitor facility and an accessible reef, but it also has a very important research centre.”