New GPS trackers reveal long-tailed bats' secret lives

The Department of Conservation has begun tracking 60 threatened long-tailed bats in Fiordland using miniature GPS transmitters as part of the Bats Beyond Borders research programme, supported by Air New Zealand.

Researchers have set up 20 base stations across the Eglinton Valley to collect location data from the bats every 30 seconds for about 12 days, depending on battery life. Each bat, which weighs up to 12 grams, carries a one-gram transmitter.

The programme aims to build a detailed picture of where the bats travel, forage and roost. The technology gives researchers a much closer view of bat movements than earlier methods.

The three-year project was established in 2025 and the tracking system was tested on seven bats last summer. The latest phase expands that work to a much larger group to better understand movement patterns at a finer scale.

Long-tailed bats have New Zealand's highest threat ranking, Nationally Critical. They live across mainland Aotearoa and smaller islands, and can travel up to 40 kilometres in a night.

Previous tracking relied on VHF transmitters, which required researchers to physically follow and locate bats in the field. That approach was difficult because the animals can move faster than a vehicle.

Dr Emma Williams, Project Lead at the Department of Conservation, described the new method as a step change for the research.

"This is the first time we've had GPS trackers small enough to attach to bats and show their fine-scale movements. Up until now, we've only been able to attach VHF trackers, which require us to physically follow and locate bats to understand where they go and what resources they need. This method was problematic because bats often outpaced us and flew faster than a vehicle.

"This technology gives us a window into the secret lives of bats. These remarkable nocturnal mammals spend most of their lives out of sight, but we're now able to see in very high detail where they go, how they behave and what they need to thrive, all while the rest of us are sleeping."

Field network

The base stations have been installed on land across the valley with support from local landowners. Global Messenger provided technical help during the installation process.

The Department of Conservation said the data would help researchers identify habitat use and movement corridors, and could improve conservation planning by allowing predator control and habitat protection to be targeted more precisely.

Predator control has already contributed to gains in the Eglinton Valley, where numbers of both long-tailed and short-tailed bats are increasing. Work in the area has focused on long-term suppression of rats and stoats.

Williams said the project also reflected a broader partnership.

"Bats Beyond Borders is a significant leap forward and a true team effort. We're grateful to Air New Zealand for its funding, local landowners for hosting base stations, and Global Messenger for providing specialist expertise during installation.

"This research reflects the true spirit of naturing: giving back to the environment through meaningful action. We can use this information to better target predator control and habitat protection for bats."

The species is New Zealand's only native land mammal. Alongside their ability to cover long distances each night, long-tailed bats can lift 80 to 100 per cent of their body weight.