Exploring the last stronghold of Gilbert’s potoroo

Two Peoples Bay, brimming with wildlife, wildflowers and spectacular coastal scenery, is a remarkable place. This tiny corner of Western Australia, thirty-five kilometres east of Albany, has harboured not just one but two species long presumed extinct.

The first ‘extinct’ species to be rediscovered at Two Peoples Bay was the noisy scrub-bird. Not seen since 1889 and considered extinct, the big-voiced bird was found on Mount Gardner in 1961, halting a planned township development and securing the area as a nature reserve.

It was, however, the second rediscovered species, Gilbert’s potoroo (Potorous gilbertii), that drew me to Two Peoples Bay. The small marsupial was first described by bird expert John Gould using a specimen obtained in 1840 by his collector John Gilbert (see boxed text). The potoroo Gilbert collected came from around Albany, possibly Two People Bay, with Gilbert writing “I have not heard of Hypsipprymnus [Gilbert’s potoroo] being found in any other part of the colony than King George’s Sound.”

Gilbert’s potoroo, last sighted in 1879, was searched for extensively in the 1970’s without success. Long presumed to have succumbed to loss of habitat, cats and foxes, a colony was found in 1994, also on Mount Gardner, about three kilometres from the southern tip of Two Peoples Bay. The population was estimated to be less than forty animals.

The small population, restricted access, dense vegetation and nocturnal nature of Gilbert’s potoroo make it almost impossible to see one in the wild. I could, however, explore the landscape that concealed this small, docile marsupial for over a century. Although some of the reserve is off-limits to protect against the root mould phytophthora, a network of walking tracks and the beach give plenty of scope for bushwalking, although a no camping rule (to guard the potoroos’ environment from fire) dictated an overnight camp outside the reserve.

Setting out from the park visitors’ centre on a cold, sunny winter day, I started my walk by heading up a sandy hill, winding through wind-twisted scrub sprinkled with early wildflowers. Reaching a junction after about a kilometre, I left my pack by the track (as I would be doubling back to the same place) and continued on the path, crossing the headland forming one side of Two Peoples Bay. Numerous small kangaroos crossed the path but it was another macropod, a quokka, I was hoping to see.

Found only in a handful of places in south-west of WA, Gilbert observed the relationship between potoroos and quokkas, writing of the potoroo “this little animal may be said to be the constant companion of Halmaturus brachyurus [quokka], as they are always found together amidst the dense thickets and rank vegetation bordering swamps and running streams.”

The two animals are found together because the smaller potoroos utilise the tunnels the quokkas make through the thick scrub, and I could see numerous tunnels along the track. Leaving the track I had an easy clamber over rocks bringing me to a small bay, Little Beach. This stunning place with bright blue water is framed by Mount Gardner, rising out of the Southern Ocean.

Taking in the view to the windswept peak, I thought back on a my recent conversation with quokka researcher Dr Elizabeth (Liz) Sinclair, who had found the potoroos here in 1994.

“I was doing my PhD at the time, running a field programme,” Sinclair told me, “and I had been surveying and trying to trap quokkas throughout their range from Perth to east of Albany. Two Peoples Bay was another location where we were looking for quokkas, and one of the last places we visited.”

Sinclair and her small team were using traps on Mount Gardner, smearing apple with peanut butter to entice the quokkas. During the regular morning check of the traps Sinclair encountered an unusual animal. Recording in her field notes ‘we caught one female bandicoot with hairless young’, Sinclair had her doubts, recalling “I remember looking at the animal and thinking it was not like the bandicoots I had seen. It looked more like a baby quokka but with pouch young it had to be an adult and the fur was super soft, not like a bandicoot. The next day we had two more in the traps and I was worried we had a baby quokka that had been separated from its mother. I was concerned the young male would not have been weaned so I stuck it in a dark bag to stop it panicking. Then when we caught another female with another young and it was the same size as the male, I thought ‘okay, something’s wrong, this is not right.’ My field assistant said to me ‘they are just bandicoots and I said ‘no, they are not bandicoots.’ ”

Back at the field station, Sinclair consulted a marsupial guide and, working off descriptions of long-nosed potoroos from the eastern states, could only come to the conclusion they were Gilbert’s potoroo, the first sighting of them in over a century.

Although access to where the potoroos live on Mount Gardner is restricted, I could climb a small headland from Little Beach and drop onto Waterfall Beach and see the lower areas of the peak, the summit over two kilometres away. I could also see the striated melaleuca thickets, about two metres high and underneath them the solid, ground level sedge the potoroos live in. What I couldn’t see are the lakes and sand dunes on the western side of the peak that have provided protection from fire. Gilbert’s potoroo survives in areas long unburnt as deep leaf litter is needed for truffles, the fruiting body on underground fungi and the potoroos main food, to grow. Over 90 per cent of Gilbert’s potoroo diet is fungi, making it, along with the long-footed potoroo, the most fungi dependent mammal known. The absence of fire also creates dense heath, protecting the animals from predators.

Waterfall Beach has a stream running onto it from the gully at the base of Mount Gardner, the small waterfall flowing strongly in winter. Pleased I had seen a small slice of Mount Gardner close up, I retraced my steps a kilometre, retrieving my pack. Turning towards the water, I followed the track, lined with peppermints and grass trees, down to the beach. Spongy seaweed soon gave way to beautiful white sand, curving away in an arc around the bay. The four and a half-kilometre beach walk provides plenty of time to look for plovers, oystercatchers and other wading birds. Staying below the high-tide line to avoid their nesting area, I turned my attention to the water, recalling the story that gives the bay its name. In 1803, a French ship captained by explorer Joseph Ransonnét was surveying the coast between King George Sound and Bald Island. Seeking calmer waters, the ship entered the bay, encountering an American sealer. This chance meeting of ships from two young republics, so far from home was recorded by Ransonnét in his log and commemorated with the name Baie des Deux Peuples.

Crossing the boundary of the reserve, I continued to the end of the beach , eating lunch in the small but beautiful East Bay. Reminiscent of coastal Tasmania, the water is a brilliant turquoise and the boulders orange with lichen. The thick scrub and steep cliffs made it impossible to continue my walk on the headland, forcing me onto a gravel vehicle track for about a kilometre to round it. Soon I could leave the road and plunge back into the bush, weaving through the grasstrees and banksias, avoiding the impassable thickets.

Following the coast for two kilometres, I picked up a water drop at Betty’s Beach and followed a very narrow, overgrown footpad, pushing through to North Point, the northern headland of Two Peoples Bay and my bivvy spot for the night.

Spending the rest of the afternoon exploring North Point, I struggled through the scrub to the eastern side of the point for views to Bald Island, twenty kilometres across the ocean. Gilbert’s potoroo does not breed well in captivity so a few were released on the island in 2005. Free of cats and foxes, noisy scrub-birds have also been released here and both the bird and potoroo have been successfully breeding. From the same place I could look to the foothills of Mount Manypeaks, only two kilometres away, where a huge area has been fenced to allow potoroos from Bald Island to be released. Between the three locations, including Mount Gardner, the total population of Gilbert’s potoroo has grown to about one hundred. Even with this increase in numbers, Gilbert’s potoroo is Australia’s rarest marsupial, based on estimated populations.

Sinclair believes the huge effort put in to save this one species is vitally important. “Everything has its place in the ecosystem,” she explains. “WA has an incredibly diverse set of plants and animals that are unique to this corner of the world and they all play their part in the environment however big or small … potoroos play an vital role in the spread of fungal spores, aerate the soil, we don’t understand all the roles they play. Start pulling things out of the system and you will reach the point of no return where that system will collapse.”

Returning to my bivvy spot, high on the headland to be safe from waves, I rugged up against the wind. Watching the clouds from my bivvy bag I drifted off to sleep, waking now and then in the night to see Mount Gardner across the bay.

An early start the next day was rewarded with spectacular sunrise views over Bald Island. Retracing my steps back around the beach and turning inland on a walking track, I spotted a quokka, chewing grass, a wary eye on me. It soon hopped off but it was gratifying to see a quokka at Two Peoples Bay, the animal Gilbert observed the potoroo was always found with. Sinclair jokes she never found a quokka on Mount Gardner, although she is pleased other people have. Now involved with research into seagrasses, Sinclair isn’t hopeful we can find more species thought to be extinct, her find coming just a few months after the Wollemi pine was rediscovered. “The chances of finding things is dropping off,” she said. “It would be nice to think something may be able to survive but the longer time goes on, the more people are changing the environment and feral cats are just devastating.”

Just over 50 years ago a planned township at Two Peoples Bay was halted because of the noisy scrub-bird rediscovery. Sinclair is emphatic this saved Gilbert’s potoroo, adding “it probably saved a whole lot of things”.

Notes on John Gilbert

John Gilbert, born around 1810, was an English naturalist, ornithologist and explorer. A keen birdwatcher, the young Gilbert shared nineteenth-century Britain’s fascination with science and nature, a time of the Beagle’s voyages and Darwin’s theories of evolution. The accompanying publishing boom was exploited by ornithologist John Gould, who dispatched collectors around the empire to provide specimens for his wildlife books.

Seeking specimens for a book on birds of Australia, Gould recruited Gilbert, crossing his path when both worked as taxidermists for the Zoological Society in London.

Sailing for Hobart Town in 1838, Gilbert quickly adapted to the Australian bush and collected prolifically, procuring animal and bird skins and skeletons that could be shipped to London and used by artists to create illustrations of wildlife. Sailing westwards to Perth the Governor assigned two Aboriginal men to assist Gilbert, with him writing “they will be very essential to me as they know perfectly well where to find particular species.”

After a year in WA and shipping boxes of specimens to London, Gilbert boarded a ship in 1840 to Sydney, docking enroute in Albany. Taking the opportunity to venture out into the King George Sound area, he observed and collected the marsupial that would be named Gilbert’s rat-kangaroo. These remained the only specimens of Gilbert’s potoroo until the rediscovery in 1994.

Returning to England, Gilbert leapt at the chance for another collecting trip to Australia. He again saw the potoroo and foreshadowed the future of many marsupials when informing Gould he found one new species because a domestic cat had killed it.

Gilbert travelled to Queensland, convincing explorer Ludwig Leichardt to let him join an overlanding party. Gilbert was killed near the Gulf of Carpentaria in 1845 when Aboriginals retaliated for offenses committed by members of Leichardt’s party. Recent speculation, based on the description of Gilbert’s wounds, suggests he may have been accidently shot by one of his own party.

After burying Gilbert his notes and specimens were carried to Port Essington, a settlement on the northern coast, where they eventually made their way to Gould. Letters indicate his employer informed Gilbert’s father of his son’s death.

Gilbert’s potoroo was first illustrated in a book on kangaroos in 1841 with Gould writing “the animal represented here was procured at King George Sound, where it is called Grul-gyte by the Aborigines. In dedicating it to Mr Gilbert…who is still prosecuting his researches on the northern portion of that continent, I embrace with pleasure the opportunity thus afforded me of expressing my sense of the great zeal and assiduity he has displayed in the objects of his mission; and as science is indebted to Mr Gilbert for the knowledge of this and several other interesting discoveries, I trust that, however objectionable it may be to name species after individuals, in this instance it will not be deemed inapproriate.”

This article originally appeared in an abridged from in Wild issue 152. The author would like to Dr Elizabeth Sinclair and Department of Parks and Wildlife staff Dr Tony Friend and Tim Button for assistance.