Call of the woodlands

Sound could hold the solution, according to Bush Heritage ecoacoustic researchers on a mission to save Australia’s birdlife.

For many scientists, seeing is believing. But for Bush Heritage ecologists Daniella Teixeira and Courtney Melton it’s hearing that is believing.

“Birds and whales singing, insects and frogs chorusing, mammals bellowing, plants ‘breathing’ – these are fragments of nature’s soundscapes,” says Daniella. “And if you listen carefully, these sounds can tell us remarkable stories of the world.”

The sounds Daniella and Courtney are hoping to hear are the calls of woodland birds. And the story is one of survival.

Pairing their conservation skills with the latest audio technology, Daniella and Courtney have set out to investigate the potential of ecoacoustics, the study of an ecological soundscape, to better monitor Australia’s woodland bird communities, and sound the alarm for potential threats.

Woodland birds, including species like the Swift Parrot, have suffered severe decline since European invasion. 

Extensive land clearing and habitat degradation has meant Australia has lost one-third of its woodland habitats and now one in five woodland bird species are classified as threatened.

What meagre woodland remains is highly fragmented and under constant threat of development.

The team believe that acoustic monitoring could enhance conservation efforts which will aid the survival rate of woodland birds and have positive flow-on effects for the wider ecosystem.

“The woodland bird community is incredibly diverse, with many species playing important roles in ecosystem services such as pollination and pest control, contributing to the regulation of vegetation health and productivity,” says Courtney. “Birds are commonly selected as indicator species. Monitoring them well can tell us a lot about the state of the environment.”

The ideal testing ground

Yourka Reserve on Jirrbal and Warrungu Country in Queensland is one of the most diverse landscapes in the country. Weeping paperbark trees lean towards the Herbert River while tall wet eucalypt forests thread their way through the land, slowly transitioning into open woodlands of Iron Bark and Lemon-scented Gums.

Since purchasing the reserve in 2007, Bush Heritage has recorded 148 species of bird. The diversity of birds and habitats make Yourka an ideal testing ground for Daniella and Courtney’s project.

Dotted throughout this landscape will be a series of strategically placed sound recorders that will capture bird calls from dawn until dusk. These devices will enable Daniella and Courtney to monitor variations between soundscapes in the different habitats and could offer early warnings of ecosystem decline.

While Bush Heritage will also undertake traditional bird surveys at Yourka, the incorporation of audio technology could offer exciting insights and larger data sets.

“With so many advances in technology the possibilities for conservationists are endless,” says Daniella. “Most of our work uses autonomous portable sound recorders, small devices that we can place onto a tree and let them record for as long as we need them to.”

One of the biggest obstacles is the sheer number of recordings collected.

“There’s no way that we could manually listen to all the sound files we capture,” explains Daniella.

Once again, it is technology that holds the solution: artificial intelligence. Daniella now spends a lot of time training algorithms to detect certain bird species, as well as other animals including invasive species.

“Even five years ago, being able to collect so much data and analysing it efficiently would’ve been a massive hurdle to overcome,” says Daniella. “But today, the algorithms that are accessible to ecologists have advanced so much and really, really aid our work. It’s incredible how far technology and conservation have come.”

Podcast: Call me by your birdsong

Listening for diversity

Employing emerging technology and data analysis will help to provide Daniella and Courtney with a more comprehensive picture of the health of the woodland bird community and the wider landscape.

While a decline in bird calls is a clear cause for concern, there are also bird calls that Daniella and Courtney want to keep close tabs on.

“If we were to hear an increase in the calls of aggressive species, such as noisy miners, then that could tell us that the bird community is unhealthy,” says Daniella.

Noisy miners, though native to Australia, are known to dominate an ecosystem and threaten some woodland bird species access to food and habitat resources. “What we don’t want to see is a homogenous bird community. We want diversity.”

A diverse soundscape, according to Daniella, equals a healthy soundscape. And a healthy soundscape equals a healthy ecosystem.

Funded by Chris and Gina Grubb and the Paul Hackett Memorial Scholarship for Bird Research, the project at Yourka will act as a trial with the potential to be rolled out across other landscapes managed by Bush Heritage, and hopefully, other animal communities.

“The long-term vision,” says Daniella, “is that these methods could track entire ecosystems. We can track vocal fauna so birds and frogs, even mammals, and even non-biologic sounds, such as wind, rain, and water. There’s a lot of amazing environmental data that we can extract from acoustic recordings.”

To learn more about Daniella Teixeira’s work and research, watch CNN’s documentary Call To Earth - Listening to our planet.