Sounds from Australia's largest owl, known for preying on possums and koalas, have been recorded along South Australia's Limestone Coast. The recordings are part of a bird "sound bath" released by the Friends of Bool and Hacks Lagoons (FBHL). The group captured audio of powerful owls at two locations, Glenroy and Nangwarry, during an extensive acoustic monitoring project that spans nearly 150 sites in the area.

FBHL president Bradley Clarke-Wood expressed surprise at the discovery. The group initially focused on the locally endangered red-tailed black cockatoo. "We were beyond excited because we detected Australia's largest nocturnal predator," he said. "It maintains balance within our local environment and it's just an incredibly special bird to have in our backyard."

Powerful owls are classified as an endangered species under South Australian law. They are large birds, averaging a wingspan of 1.2 meters. "They're a massive bird and they stealthily move through our forests at night without a sound," Clarke-Wood noted. He added that while they help control possum populations, they also prey on koalas and other mammals when possible.

Local bird watcher Bob Green has spotted powerful owls in the region on rare occasions. "They're about the length of a yellow-tailed black cockatoo, but pretty much twice the weight, weighing somewhere around 1.5 kilograms," he said. Green mentioned that dawn and dusk are ideal times to hear the owls calling. "Quite often they'll start calling from where they're roosting before they head off to hunt during the night."

While FBHL plans to monitor owls in additional locations, Clarke-Wood does not believe this indicates a population boom. "I think we're just better defining where these birds are inhabiting," he said. This understanding could lead to improved conservation efforts for the species. Green added that further detection of the owls is positive news for the region. "Anywhere where they're found is great news, particularly if we can find that there is a pair present somewhere and there's additional breeding going on," he said. "Who knows whether the numbers may increase over time from what is still a very uncommon bird in the south-east."

The powerful owls' distinctive "hoo-hoo" call is one of many sounds recorded during the project. These recordings have been combined to create a sound bath featuring calls and songs from various local birds, including rufous whistlers and tawny-crowned honeyeaters.

Clarke-Wood described the sound bath as a way for people to engage with the data without any broader expectations. "It hopefully fosters an appreciation for the local environment," he said. He hopes the recordings will help the public recognize the bird diversity in the region. "We're able to put this out a bit further so that others can access this data, and they can hear how impressive and diverse our local environment is," he added.