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Little bats a big surprise in our backyard

Tuesday 21 June 2022

If you happen to come across a camouflage-printed box mounted to a tree in one of Holdfast Bay’s gullies or reserves, there’s no need to pay it any attention – unless you’re a native microbat.

And if you are a microbat – which is a tiny flying mammal - the Anabat detector is simply recording your sound frequencies, as part of a data gathering and microbat monitoring project.

There are more than 60 different types of microbats across Australia, with eight species common in South Australia.

They usually feast on insects and can eat as much as 40% of their own body weight in a single night.

In Kingston Park's Pine Gully, there are two microbat boxes mounted to a tree. However, given the animals are nocturnal, it was nearly impossible to know for certain if any lived in the area.

That was until a survey was conducted in February this year by Sue Wiseman, from the Friends of Pine Gully volunteer group.

Using a borrowed Anabat detector – which has a microphone attached to it for acoustic recording - she mounted the device onto a tree in Pine Gully to see what data she could capture over the course of a week.

“I thought that we might only have a couple of species … but when we did the February survey, we recorded six species out of a possible eight,” Sue said.

Sue applied for a grant to buy the Anabat device and was successful through the Ripple Effect program offered by Adelaide-based business, Human.Kind.

That device has been donated to the City of Holdfast Bay to allow the Environment team to monitor microbats in Barton and Gilbertson gullies – and to allow other environmental or volunteer groups to do the same.

One of the six microbat species found in Pine Gully was the Chocolate Wattled Bat, which, according to Australian Geographic, weighs about 9 grams and has a maximum wingspan of just 4.2cm.

Other species detected included the White-striped free-tailed bat, Gould’s Wattled bat, Lesser long-eared bat, South-eastern free-tailed bat and the Southern forest bat.

An article on the Environment SA’s website provides more information on microbats and what to do if they take up residence in your backyard.

“If you have microbats visiting your garden, you should consider yourself very lucky. They are looking for insects, and one bat can easily polish off half its own bodyweight in insects every night,” the article says.

Mostly, they live together in groups in tree hollows, but if hollows aren’t available, they may move into chimneys, roof spaces or sheds.

You can also build a microbat box, which the microbats can use to roost in during the day or hibernate in during winter.

Microbats boxes need to be designed with a landing pad at the bottom of the box so they can crawl up inside.

Volunteer and community groups wanting to borrow the Anabat detector are asked to contact the council’s Urban Greening Officer on 8229 9999.

Close up of a native Australian micro bat
Chocolate Wattled Bat. Image: R & A Williams, courtesy of Australian Museum

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