Bio-acoustic monitoring: eavesdropping for endangered species

Good news from bio-acoustic monitoring of rare cockatoos. Photo credit: Jennifer Goldsworthy.

Three years of bio-acoustic monitoring at the Bank Australia conservation reserve on Wotjobaluk Country, Western Victoria, has revealed that the rare South-eastern Red-tailed Black-cockatoos are using the artificial nestboxes on offer.

Bio-acoustic monitoring involves recording and analysing the sounds produced by animals and is a technique commonly used by ecologists and conservation researchers to learn more about patterns and trends occurring amongst a wide variety of species.

“Bird surveys are a low-tech version of this, where people physically listen to bird calls and record that information. But those kinds of surveys involve a lot of effort and are generally done just a few times a year,” explained Jess Gardner, Greening Australia’s Senior Program Officer in Victoria’s Wimmera region.

“That’s where the high-tech version of bio-acoustic monitoring comes in handy, because we can capture data for 24 hours a day, 7 days a week, that really complements those important in-person ground-truthing surveys.”

Artificial nestboxes installed for the South-eastern Red-tailed Black-cockatoo. Photos credit: Birdlife Australia.

Managed by Bank Australia, the Barengi Gadgin Land Council, Greening Australia and Trust for Nature, the Bank Australia conservation reserve protects 2,117 hectares of remnant and restored vegetation in Victoria’s Wimmera region that is prime habitat for the South-eastern Red-tailed Black Cockatoo (SE-RTBC for short).

Sound recorders have been set up at two of the four properties that make up the Bank Australia Conservation Reserve, Ozenkadnook and Booroopki.

All ears for the endangered SE-RTBC

At Ozenkadnook, with the support of the Red-tailed Black-cockatoo Recovery Team, sound recorder devices are set up on four trees. One of the trees contains a nesting hollow suitable for the SE-RTBC, and the other three trees host artificial nest boxes specifically installed for the cockies.

“By listening to the calls recorded throughout the nesting season, researchers can tell if the birds are using the hollow, whether they have eggs, and whether there is a successful fledging event,” said Jess.

“Birdlife Australia have been routinely checking the batteries and storage cards on the bio-acoustic monitoring devices and downloading the data for analysis. And now from that data, it’s fantastic to discover that all four trees and hollows have been nested in over the past three years.”

On the downside, there’s been no evidence of successful fledging yet.

The nests will continue to be monitored this year, with additional assistance from the Bank Australia Reserve team, and more artificial nest boxes will be installed at Ozenkadnook and at Minimay, another of the reserve properties.

South-eastern Red-tailed Black-cockatoos have nested in all four trees and hollows over the past three years. Photo credit: Bob McPherson.

The link between food and fledging

With an estimated population of just 1,500 birds found in a limited range straddling the border between south-east South Australia and south-west Victoria, the SE-RTBC is in dire need of a baby boom. So if they’re using the artificial nest boxes but not fledging, what else can be done to support them?

“Besides hollows or nestboxes for nesting in, what is thought to be of utmost importance is having enough food, and having good sources of food close to the nests. Nesting can fail if females need to leave the nest and forage wider afield to supplement the food brought to them by their mates,” said Jess.

Unlike the more common Yellow-tailed Black-Cockatoo, that’s adapted to feeding on introduced pines, the SE-RTBC don’t have an alternative food source. They eat the seeds of Brown and Desert Stringybark (Eucalyptus baxteri, E. arenacea) and Buloke (Allocasuarina luehmannii) trees, and very little else, so replanting these species in the conservation reserve has been a key focus for the team.

Restoring habitat for the SE-RTBC in the region overall has been a focus for Greening Australia’s team in Western Victoria for over a decade, with 200,000 stringybark and 10,000 Buloke seedlings planted on both public and private land across the range of the birds in collaboration with state government and corporate partners so far.

Greening Australia works closely with the SE-RTBC Recovery Team to ensure plantings are strategically placed in areas of known sightings and nesting locations.

The Bank Australia conservation reserve protects a significant 2,117 hectares, providing habitat for hundreds of plant and animal species including threatened species like the SE-RTBC. Photo credit: Bank Australia.

Bio-acoustic monitoring for broader biodiversity

With the latest biodiversity survey of the Bank Australia conservation reserve detecting 283 native animal species, including 113 unique bird species, ensuring that habitat in the reserve is healthy and continuing to provide great homes for wildlife is a top priority. Bio-acoustic monitoring can help with this as well.

At Booroopki, another part of the reserve, four recording devices have been set up to monitor wildlife in remnant areas of habitat and in areas that are actively being restored with revegetation.

“This is a broader experiment, where we are interested in what the bio-acoustic monitoring data can tell us about the diversity of species over time, and the difference between remnant and restored areas. We would also be able to correlate data with different events, such as fire,” said Jess.

“The devices here are just one site amongst many, right across Australia, that are part of a project by the Queensland University of Technology that’s hoping to analyse trends in biodiversity. It’s a great example of how, by connecting with other organisations and projects, conservation reserves like this one can contribute to a larger scale picture of biodiversity across Australia.”

“You might be thinking, that’s so much data! And it is – we really don’t have the capacity to go through it all. But it’s important to capture it now, because soon the rapidly advancing field of artificial intelligence will catch up and can analyse the sounds of all the species at the reserve for us.”
 
Want to know more? Learn about our partnership with Bank Australia or discover more stories from the conservation reserve.

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