Started by the Tāhuna Glenorchy Dark Skies Group in 2024, the project was originally aimed at detecting the short-tailed bat in the Rees Valley, but when none were detected, evolved to monitor their long-tailed cousins.
Group chairwoman Leslie Van Gelder said a grant from environmental community fund Love Queenstown was used to buy 10 acoustic recording devices in 2024.
A brief survey in the township that spring confirmed the bats’ existence, prompting the group to buy 15 more recording devices last year.
The data from a more comprehensive survey last spring has just been analysed by Southern Lakes Sanctuary (SLS) biodiversity projects co-ordinator Sam Purdie.
Ms Van Gelder said the results were ‘‘phenomenal’’, with ‘‘bat chat’’ recorded on 28 nights of the 29-night survey.
‘‘With the set of recorders we have now, the data set’s good enough to be publishable and replicable year-on-year.’’
SLS also uses the recorders in the Rees Valley and other areas where it wants to monitor the native mammal.
However, across the country they were classified by the Department of Conservation as nationally critical, which is its highest threat category.
The next step in the project was to enlist the help of a bat specialist to precisely locate the bats’ roosts, she said.
That would involve putting tracking devices — ‘‘little bat backpacks’’ — on some bats to identify their flight paths and roosting trees.
‘‘That’s our plan for next year, then we can start doing serious predator control to protect the sites where they roost and some of their habitat.’’
As for short-tailed bats, one was recorded in the north branch of the Routeburn some years ago, but no-one knows if there is still a population in the area.
‘‘We have the right habitat, so they have existed here, but so far we haven’t found them.
‘‘The search continues.’’
Short-tailed bats were more vulnerable to predation than long-tailed bats because they foraged on the ground for food, she said.
