It’s a decade ago, but Dr Rebecca ‘Bec’ Boulton, chair of the Threatened Mallee Birds Steering Committee (TMBSC), still remembers the 2014 summer well. “I was in Adelaide at the time and I worked in the Mallee,” Bec says. “We had a couple of big fires in the Mallee that summer, and we lost the mallee emu-wren from South Australia.” The species is now extinct across the state.
The mallee emu-wren (Stipiturus mallee) was once found across a couple of hundred kilometres of mallee shrublands and heathlands, east and west of the SA–Victoria border. But clearing for agriculture has removed its habitat from much of its former range.
This tiny bird is a Triodia spinifex specialist. The spiky, tussock-forming grass provides shelter from predators and a safe site to nest as well as habitat for the insects that the mallee emu-wren feeds on. It’s a shy bird that spends most of its time close to the ground in dense spinifex tussocks.
“We’ve still got around 7,000 birds,” says Dr Katherine Selwood, a threatened species biologist with Zoos Victoria, one of the organisations on the TMBSC. “But the problem is, they’re all in just a couple of spots.”
The species’ entire world population is now restricted to a very small number of reserves centred on Murray-Sunset National Park in north-west Victoria. With their stubby wings and long filamentous tails, mallee emu-wrens aren’t well built for flight. “They’re tiny, tiny, little things, only four to six grams, and they don’t fly much,” Katherine explains. “They’ve got pretty poor dispersal ability.” And that’s a problem for the mallee miniature when fire strikes.
The Mallee is one of Australia’s most fire-prone environments and landscape-scale fires are a natural phenomenon. Large fires are “part of the system”, Katherine says, but can consume everything in their path, leaving burnt, bare ground. That’s no good for mallee emu-wrens that depend on dense spinifex.
“Historically, there were huge swathes of mallee, and you’d get big fires here and there,” Katherine says. “Emu-wrens could move into habitat that’d recovered.” But spinifex recovery takes time and it can take a decade or longer before it can support mallee emu-wrens after a fire. “If you get fires too frequently,” Katherine says, the spinifex “never gets to be dense enough to support emu-wrens.”
Habitat for birds
Although old spinifex provides refuge for mallee emu-wrens, a total lack of fire is not necessarily helpful. Long-unburnt spinifex gradually deteriorates, resulting in habitat that is too sparse for the cover-loving birds. “It’s about getting that fire regime right, so that enough area remains in the window of suitable habitat,” Katherine says.
Understanding what makes mallee habitat suitable for the mallee emu-wren and a chorus of other threatened mallee bird species has been a major focus for the TMBSC. Forged in response to the devastating 2014 fires, which swept across tens of thousands of hectares of mallee in Victoria as well as SA, the TMBSC is a group of organisations and individuals. They include BirdLife Australia, government representatives, universities, resource management NGOs and zoos.
“It was a way of getting all the people that work on threatened mallee birds to come together,” explains Bec, who’s been part of the TMBSC since its inception. “We got the mallee experts, had big meetings and wrote the Threatened Mallee Birds Conservation Action Plan (CAP) by the end of 2015.” Coordinated by BirdLife, and updated in 2024, the CAP details the work needed to understand and conserve mallee birds. “There are a lot of great people that get a lot done for very little,” Bec says about the diverse TMBSC.
An essential part of conservation planning for any species is knowing where it occurs. “Through the CAP we have got a lot of surveys done,” Bec says. “That helps us identify what parts of the landscape are more important so we can make recommendations. We can say to park managers, ‘This is where the emu-wrens are, it would be good if you don’t burn this spot right now.’”
Deliberate burning to create habitat for mallee birds is only just beginning. “That’s because we only now have all this information on how these species respond to fire,” Bec says. “Until you have that detailed information, you don’t know if you’re making things worse by burning certain bits.”
Even with emu-wren-friendly fire plans in place, mallee emu-wrens remain vulnerable to wildfire. “If you got a really big fire through one of the mallee reserves, like Murray-Sunset, you could lose a chunk of birds in one hit,” Katherine says. It was fire like that which was the final straw for mallee emu-wrens in SA. And fires are looking more likely, with longer droughts and increasingly frequent heat waves brought on by climate change.
Drought worries Bec. “We see declines in species through these droughts,” she says. “Then drought breaks and they come back up, but they never get right back up before they’re hit by another drought.” Bec has been working in the Mallee for 25 years. “It’s sad,” she reflects. “A lot of people will go into the Mallee and think, ‘Oh, wow, this looks great.’ But 25 years ago, it did look better.”
Because fire and drought are ongoing risks for the remaining isolated mallee emu-wren populations, they’ve proverbially got all their eggs in just one basket. That’s set to change, with ‘wild-to-wild’ translocation programs in the works to establish new populations.
“We don’t want to lose the species piece by piece,” says Katherine, whose employer Zoos Victoria is planning the new emu-wren translocation program with the TMBSC. “We want to spread the risk from bushfire by re-establishing populations in reserves where the species has gone extinct,” she says. “We want to be able to say, ‘Okay, we’ve lost them there, but this habitat has recovered. Let’s get emu-wrens back in there.’”
There’s a lot involved in translocation. Researchers must decide how many individuals can be safely ‘harvested’ from existing populations and keep tabs on how relocated birds are faring. Both donor and re-established populations must be monitored, but that’s challenging with teeny-weeny mallee emu-wrens that are too small to radio-track and stay too well hidden for coloured leg bands to be useful. “They’re just so small and furtive that even marking them is hard,” Katherine says. “So, we’re focusing on audio monitoring, setting up devices that record song so we can know whether they’re surviving in particular patches.”
Katherine and her colleagues will also take mallee emu-wren blood or feather samples for genetic tests that reveal how many birds are breeding. “That will be our way of monitoring success and population sizes,” she says.
At Monarto Safari Park in SA, Tom Hurley, the assistant curator of natives, doesn’t need equipment or tests to tell him he has more emu-wrens in his care than he did in 2023. “We’ve had to skip ahead a few steps,” Tom says, referring to the surprise fledging of three mallee emu-wren chicks in January 2024. The park’s 10 adult emu-wrens had arrived at the zoo just a couple of months before; Tom wasn’t expecting his charges to be in the family way so soon after setting up home in their new digs.
Those digs are five behind-the-scenes aviaries, furnished with spinifex and other plants to replicate the mallee environment. With advice from the Alice Springs Desert Park, and construction help from Murray Bridge Rotarians and Monarto’s Mallee Minder volunteers, the aviaries were purpose-built to house mallee emu-wrens so zookeepers can learn how to care for them in captivity, should a captive-breeding program be needed. Obviously, the aviaries’ ambience was to the emu-wrens’ liking, and their unexpected nesting and chick-raising kick-started husbandry research.
“Everything that goes in the beak is swallowed whole,” Tom says, describing the mallee emu-wren’s digestive tract. “Providing chick-sized food was even more important once we realised that. It was like, ‘Geez, now we’ve got to provision large amounts of tiny, tiny food!’” Happily, for the keepers who have to source it, downsized food only seems to be critical in the chicks’ first few days. Then the adults are, Tom says, “shoving all sorts of stuff down there”.
Meeting needs
By Spring 2024, Monarto’s mallee emu-wrens were nesting again, with the previous season’s offspring lending a hand. In the wild, mallee emu-wrens can breed cooperatively, but no one knew whether parents would have helpers in captivity. Close observation by Monarto’s staff confirmed they do. “The daughter was seen helping mum collect nesting material,” Tom says. “This little family unit was functioning in the way we hoped.”
Despite the mallee emu-wren’s endangered status, Tom is optimistic about the species’ long-term survival. “Evolution has set these birds up to be pretty gnarly as far as what they can tolerate, and the conditions they deal with,” he says. “They can be in a 500C-plus environment where all your moisture must come from what you eat.”
Tom, Katherine, Bec and their colleagues on the TMBSC are doing what they can to help mallee emu-wrens tough it out in their increasingly harsh environment. “Through the Conservation Action Plan, we’ve done a lot of research,” Bec says. “At least now we know what the species needs, and we can apply the right tools.”
