A Mallee emu-wren. Tiny and very angry. Credit:Tom Hunt “These birds are so small, but they don’t know that,” he laughs, recounting the story. “When they hear the birdsong, they’ll come right up beside you and start yelling." After a two-year search, Verdon had discovered a hotspot for one of Australia’s most mysterious and threatened birds – the mallee emu-wren, one of our smallest birds. His find, made last year, has helped pull the species back from the brink of extinction.

Credit:Tom Hunt

The wren weighs just five grams, which is about one teaspoon of sugar, and stands only 15 centimetres tall. Its wings can barely get it off the ground. It eats insects, lives inside razor-sharp and impenetrable bushes of Triodia grass, and only resides in places that have been burnt between 20 and 40 years ago. It is so rare that few people have ever seen one alive. “It has this narrow window of 20 or so years in which it can use the vegetation – it sounds like a stupid strategy, and it’s endangered, so I guess it is pretty stupid,” says Verdon. The thick bush where the team found the wren. Credit:La Trobe University / Supplied The wren was known to live in just four reserves in Australia. In 2014, two of those reserves in South Australia were hit by bushfires.

“When a wildfire goes through that country, it wipes out everything. There are no survivors. It just turns into a moonscape,” says Verdon. Scientists were faced with a grim prospect. Only one spot, in Victoria, was left. If more couldn’t be found, the wren was staring at extinction. So they turned to Verdon. Before starting his PhD at La Trobe University, he had worked in the Mallee as a firefighter, making him ideal to search for flame-loving creatures. He was also an obsessive birdwatcher. The plateau area in the Murray-Sunset National Park. Credit:La Trobe University / Supplied To begin the search, the 29-year-old turned to maths. Using a database of all Victoria’s landscapes, he looked for environments where the bird might live. Then he added in data for how recently the area had burnt. He ended up with a mathematical model to predict likely wren hotspots.

Unfortunately, there were 230 of them, many in places not accessible by car. So he and a small team of volunteers spent the next 18 months visiting each and every one. Mallee wrens are tiny and live in dense grass, so they are almost impossible to find. But they are very territorial and will react angrily if they hear the song of another wren. So Verdon and his volunteers combed hectares of bushland, playing wren song on mobile phones and listening for returning calls. For 18 months, they heard only silence.

“I felt like I was hearing the future – there were no birds calling. This is what people in 20 years are going to hear, not the busy soundscape I was used to,” says Verdon. “That was depressing, very depressing.” But as he pushed his way onto the plateau in the Murray-Sunset National Park, on the northern portion of the border with South Australia, he knew he’d found the spot. “You could hear all the birds, every bird, at once,” he says, his voice still filled with wonder all these months later. Vitally, the lake bed seems to support the wrens despite not being regularly burnt. The new region Verdon discovered contains about 3000 wrens, bringing the total known population to about 8000. Researchers had suspected there were some in the area he was looking, but to find 3000 was a major triumph.