Key facts
- Fact 01
DOC is fitting 60 threatened long-tailed bats in Fiordland's Eglinton Valley with GPS transmitters in summer 2026.
- Fact 02
Each transmitter weighs one gram, and the bats weigh up to 12 grams.
- Fact 03
20 base stations across the Eglinton Valley receive each bat's location every 30 seconds for around 12 days.
- Fact 04
Long-tailed bats are ranked Nationally Critical and can travel up to 40 kilometres a night, DOC says.
Sixty threatened long-tailed bats in the Eglinton Valley in Fiordland will carry tiny GPS transmitters this summer, the Department of Conservation (DOC) said in a media release on Thursday 12 November 2026. We read the release on the morning of Friday 13 November, and every figure below comes from it.
The research programme is called Bats Beyond Borders. It is led by DOC and supported by Air New Zealand. The bats weigh up to 12 grams each and the transmitters weigh just one gram. The transmitters connect to a network of 20 base stations set up across the Eglinton Valley, and researchers will receive each bat's location every 30 seconds for around 12 days, depending on the battery life.
DOC says the three year programme was established in 2025 and piloted the tracking system on seven bats last summer. DOC project lead Dr Emma Williams says it is the first time GPS trackers have been small enough to attach to bats. Until now, researchers used VHF trackers and had to follow the bats themselves, and the bats often flew faster than a vehicle.
Long-tailed bats have the highest threat ranking, Nationally Critical. DOC says they can travel up to 40 kilometres every night, and that both long-tailed and short-tailed bat numbers are increasing in the Eglinton Valley because of long-term control of rats and stoats. The findings will be used to target predator control and habitat protection.
The Eglinton Valley is one of the stops along the Milford Road named in our Milford Sound day tours guide. The bats are nocturnal and spend most of their lives out of sight, so this is research to follow rather than something to see on a day trip. Our Queenstown to Milford Sound planner covers the drive through the valley.
Questions visitors are asking
Where are long-tailed bats being tracked in Fiordland?
In the Eglinton Valley in Fiordland, on the Milford Road. DOC said on 12 November 2026 that 60 long-tailed bats there will carry one gram GPS transmitters this summer, linked to 20 base stations set up across the valley as part of its Bats Beyond Borders research programme.
How do the Fiordland bat trackers work?
Each long-tailed bat in the Eglinton Valley carries a transmitter weighing one gram, on a bat that weighs up to 12 grams. The transmitters connect to 20 base stations across the valley, and DOC researchers receive each bat's location every 30 seconds for around 12 days, depending on battery life.
Can visitors see the bats in the Eglinton Valley?
DOC describes long-tailed bats as nocturnal mammals that spend most of their lives out of sight, so a daytime stop in the Eglinton Valley on the Milford Road is unlikely to show them. The tracking is research to follow; DOC says bat numbers there are rising thanks to long-term predator control.
Why are long-tailed bats in Fiordland being tracked?
Long-tailed bats have the highest threat ranking, Nationally Critical. DOC says detailed GPS data from the Eglinton Valley in Fiordland will show where the bats travel, forage and roost, so it can better target predator control and habitat protection. The bats can travel up to 40 kilometres a night.