A total of 13 bats, nine of them female, were caught in harp traps and named by Doc field staff, who were assisted by six volunteers from Balclutha, Invercargill, the United Kingdom, United States and France.
The volunteers joined Doc Wakatipu bio-assets manager Barry Lawrence, biodiversity assets ranger Ray Malloy and community relations ranger Anna Humphries, all of Queenstown, and Otago community relations ranger Claudia Babirat, of Dunedin, for the first bat-monitoring expedition in the Rees Valley, between November 28 and December 4.
The team fitted tiny radio transmitters to the female bats, released them and used telemetry equipment to locate the creatures and their roosts during the day and count bats emerging from roosts at dusk.
With the permission and support of Rees Valley Station landowners Iris Scott and daughter Kate Scott, the team camped and set 10 vertical metal-framed harp traps, which are about 5m high, in natural pathways between clearings where bats were predicted to fly through when foraging at night.
"We look for the females because the point is to find their roosts," Ms Babirat said.
"You can tell whether they are juvenile or adult by shining a light through the membrane of the wing. If the joints of the knuckles are fused, they are adults."
Up to 200 bats can live in one roost. Doc surveys how many of the scarce native animals are circling each year, but the third-latest annual volunteer monitoring expedition sought to locate the roosts and record visual counts.
"Once we know where the roosts are, we can keep an eye on them with a view to knowing the distribution of the roosts in the valley," Ms Babirat said.
