Until recently, Australia’s smallest bird – named after its largest – was found only in Victoria, after catastrophic wildfires in 2014 caused the extinction of the species in South Australia.
La Trobe PhD student Simon Verdon – whose thesis is on the role of fire for the species – combined intensive field work with sophisticated mathematical modelling in an effort to locate the Mallee bird in Victoria and successfully reintroduce the species to South Australia.
“We’ve already released 40 birds to a new habitat in South Australia and the early signs look good,” Mr Verdon said.
“The Mallee Emu-wren is the epitome of the Aussie battler. It weighs barely five grams, it considers ten metres a long flight, and it resides in some of the world’s most flammable vegetation,” Mr Verdon said.
“It is trapped by a paradoxical relationship with fire.
“It requires fire to create new habitat, yet fire is a major contributor to local extinctions of this species.”
Using long-term distribution data and ecological modelling, Mr Verdon was able to discover a large and important population hot-spot of the Mallee bird in Victoria, which has now been used to supply birds to South Australia.
“We think there are around 8,000 birds remaining, with most of these found in the western section of the Murray Sunset National Park,” Mr Verdon said.
“It’s an unusual geological area with really low-lying sands that make the soil fertile, healthy and productive. But it’s hard to access, so up until now, it went under the radar.
“It took three days of searching for me to find my first bird. But in western Murray-Sunset you can find more than 20 in a day. Whenever I find them, it’s a really magical moment and my heart starts racing.”
Mr Verdon used mathematical models to understand why the Mallee Emu-wren was flourishing in this pocket of north-west Victoria.
“Prior research indicated fire was the most important aspect to the Mallee bird’s habitat,” Mr Verdon said.
“Our research showed the birds were actually reacting to very small changes in land elevation. A difference of just a few metres determined whether the Mallee Emu-wren would populate or reject a location.”
“The future is beginning to look brighter for this species, now that we have birds back in South Australia and we understand their distribution and habitat here in Victoria.”
Led by the Government of South Australia, the first reintroduction of birds was completed in April 2018 after funding and support was secured from the Threatened Species Recovery Fund and project partners – Zoos SA, Zoos Victoria, Rotary International, the Victorian Department of Environment, Land, Water and Planning, BirdLife Australia, Parks Victoria, La Trobe University, Monash University and Natural Resources SAMDB.
More than 1500 hours were spent in the field capturing family groups, transferring the birds from the Victorian sites to Ngarkat Conservation Park in SA, and then undertaking post-release monitoring.
Results of this first release will be analysed to inform a second release in late winter 2018, when an additional 20 breeding pairs will be translocated into the same release site.
“We are really proud of what we have achieved so far, with a network of ten agencies working together,” Mr Verdon said.
“That said, summer is a nail-biting season for many of us because one fire could wipe out most of the species. We’re doing everything we can to prepare for that, but in the end it is also up to mother nature,” Mr Verdon said.
Image: Mallee Emu-wren, male (Hattah-Kulkune National Park). Credit: Tom Hunt