Monitoring Maruia Valley’s long-tailed bats

By Lauren Kelley, Community Ranger

Each January and February, a team of biodiversity staff from the Māwhera/Greymouth office monitors long-tailed bats in the Maruia Valley.

They start by putting out free-standing harp traps to catch lactating females (new mothers).

Free-standing harp traps are set up in anticipation of a night mission with the children

Radio transmitters are attached to the first two or three they catch, and these lead the team back to roosts where the bats gather in large maternal groups to rear their young.

Bats typically change their roosts nightly, and this year’s bat team, Adam Ross, Bronwyn Slack, Natasha Bedford, Matt Chisnall and volunteer Emma Pearson, were kept busy tracking their locations during the daytime.

It’s a lot of effort but Maruia is a hot spot for long-tailed bats, and monitoring helps us better understand their distribution and how the population responds to predator control.

Transmitter and band on long-tailed bat

The local primary school was keen to learn about their backyard native species so a programme was trialled where the children, after learning about bats in the classroom, got some hands-on experience – it was a big hit!

First, recording devices were put out to listen for bats. Once DOC staff had trapped and fitted transmitters to several bats, the children (and their parents) took turns shadowing the team while they tracked the bats back to their roosts.

Participating families even came on a night mission to check the harp traps, and I was able to join them!

Adam Ross showing the school kids how to use the Yagi aerial which picks up the transmitter signal. Photo: Bronwyn Slack

2017 was a rough season for weather on the Coast, and the bat team wasn’t able to monitor as much as they would have liked.

By the time it was dry enough to get the children out at night, most of the bats had finished rearing their young and left the large communal roosts.

Learning how to pick up the bat’s transmitter signal

Adam Ross and Natasha Bedford attaching a transmitter to a bat

The excitement grew as we quietly approached the traps on the chosen night. We shone our lights into the first trap, then the second, but found that we hadn’t caught anything.

The DOC staff were more disappointed than the children, but the kids still enjoyed the excitement of going for a bush walk and staying up late on a school night.

Feedback from the school suggests that both the children and their parents learned from the experience and they’re looking forward to shadowing the bio team again next year.

Fingers crossed for good weather and a healthy breeding season!