A rare bat species has been discovered more than 650 km from where it was last recorded in the NT by a researcher who captured its unique call using a handheld bat detector, the Australian Wildlife Conservancy said.

AWC wildlife ecologist and resident bat specialist Oli Aylen said he was fortunate to detect the Arnhem sheath-tailed bat at Pungalina-Seven Emu Wildlife Sanctuary, which is close to the Queensland border, southeast of Borroloola and near the coast of the Gulf of Carpentaria. The sanctuary is 650km from the bat’s previous most easterly detection near Jabiru. The species was previously only known to occur along the NT’s west coast and in north-west Arnhem Land.

Mr Aylen, nicknamed “Batman” by his colleagues, said microbats navigate and hunt using echolocation, emitting sounds that are too high-pitched for humans to hear and listening for the returning echoes. The bat was identified through acoustic analysis rather than direct observation or capture.

“We were actually setting up canopy mist nets around the mangroves at Pungalina. I just happened to also have my handheld bat detector on, capturing the calls of the bats as they flew overhead,” Mr Aylen said.

“The species has a really short echolocation call, which is highly unusual for bats that call at that frequency. So straight away, I wondered if that’s what it could be.”

The bat recording was sent to Dr Damian Milne, another bat expert and senior scientist at the NT Government’s Flora and Fauna Division, who identified it as the Arnhem sheath-tailed bat, a species he has researched extensively. The bat was first described in 1979 and remains poorly understood, with limited knowledge about its habits beyond its diet of flying insects and possible preference for roosting in tree hollows.

Mr Aylen said it was one of Australia’s most mysterious animals and notoriously difficult to find because of its remote habitat and high-speed flight, with very few recordings or captures ever confirmed.

“There had been anecdotal comments about how the bat may occur across more of the Top End, and we’ve now confirmed that,” Mr Aylen said.

“It’s certainly one of Australia’s most rarely observed species. The bat’s discovery at Pungalina and subsequent range expansion is really exciting. It’s a major step forward in deepening our understanding of where the Arnhem Sheath-tailed Bat occurs.

“The species will be a priority for AWC’s Ecohealth targeted surveys moving forward, and we will incorporate a range of methods to detect and ideally catch this elusive bat. If we’re lucky, we may be able to find out where these bats roost, a vital knowledge gap, which will help us further protect this species and the habitat it relies on.

“Currently, we don’t know if the Arnhem Sheath-tailed Bat is a rare species or if it’s threatened and needs our help. Or there could be a much larger population than we think. It needs ongoing research and more conservation attention.”

Mr Aylen said the recent discovery at Pungalina was AWC’s most significant addition to its bat research, which includes the discovery of the vulnerable ghost bat at Bullo River Station.

Pungalina-Seven Emu Wildlife Sanctuary, managed by AWC since 2008, focuses on conservation efforts such as improving fire management, controlling invasive species, and monitoring ecosystem health.