The eastern bristlebird is a small, stealthy, ground-dwelling bird that lives in dense undergrowth and is very good at camouflaging. But that's not why they're becoming increasingly harder to spot.
Only about 2,500 eastern bristlebirds are left in the wild, spread across isolated populations in eastern NSW and southern Queensland.
In a bid to save the species from extinction, conservationists are employing a technique known as 'genetic rescue'.
Senior threatened species officer with the NSW Department of Planning, Industry and Environment, Kelly Roche, said the small, disconnected populations of the birds could result in low genetic diversity.
This, in turn, compromised the species' ability to breed and left the birds vulnerable to threats such as wildlife, habitat loss, disease and climate change impacts.
"That's why under the Saving our Species program we are taking advantage of a cutting-edge conservation technique known as 'genetic rescue' in a bid to turn the tide on eastern bristlebird extinction in NSW.
"We are trying to reverse the decline in the genetic diversity."
How does 'genetic rescue' work?
Genetic rescue involves first examining genetic diversity across eastern bristlebird populations.
The species has four distinct and separate populations: one in northern NSW and into southern Queensland, including the Border Ranges National Park; two central populations, including the Southern Highlands and Jervis Bay areas; and one southern population around the NSW/Victorian border, including Nadgee Nature Reserve and Croajingolong National Park.
"The eastern bristlebird is very hard to spot in the wild, it actually runs through the undergrowth more like a little mammal than a bird," Ms Roche said.
The genetic rescue program will involve carefully choosing breeding individuals from the larger populations and introducing them into the smaller ones.
It is being run in conjunction with a captive breeding program.
"We have 24 birds from the northern population in the captive breeding program at Currumbin Wildlife Sanctuary," Ms Roche said.
"What we've been doing is going around to all of the big populations of the species, catching some birds, taking a tiny bit of DNA from the birds and then analysing that information to determine what the genetic characteristics are.
"We will use this knowledge to selectively breed birds from different populations, with the aim of improving disease resistance, increasing genetic diversity and lifting fertility rates, particularly in the smallest population of birds located in northern NSW."
Breeding program underway
Ms Roche said the researchers were already seeing the areas of strongest genetic diversity.
"So far the information is suggesting we can use some of the wider genetic diversity we are seeing in one of the central populations to mix with the northern population in the captive breeding program," she said.
Ms Roche said a small number of those wild birds would be collected and introduced to the captive breeding program so they could interbreed and improve the genetic profile of that population.
The captive-bred birds will then be gradually released into the wild.
"It will increase their numbers in a way that's more efficient than just relying on the natural expansion that occurs as we slowly restore habitat in the wild … the end goal is to see resilient populations of healthy birds in the wild."
The genetic rescue project is being undertaken in collaboration with Currumbin Wildlife Sanctuary (CWS), Caesar Australia, the Victorian Department of Environment, Land, Water and Planning (DELWP), the University of Queensland, Parks Australia and the Australian Department of Defence.
