Backyard visitors
Microbats are evolutionary marvels that help to control insects in your garden, says LEONARD CRONIN
Flitting through the night sky on membranous wings, almost too fast and manoeuvrable for the eye to follow, a tiny bat swoops to pluck a moth from the air. These whispering shadows, no bigger than a human thumb, consume staggering quantities of insects at night, playing a vital role in pest control.
Demonised by myth and legend, bats have suffered bad press for hundreds of years. Yet these amazing little mammals are a triumph of evolution. With just a few modifications to the basic mammalian form, bats have conquered the skies. Extra-long finger bones and a layer of thin, rubbery skin between the limbs and tail create their flappable wings, while high-frequency vocalisations and exceptional auditory discrimination provide microbats with a ‘sound picture’ of their surroundings. In total darkness, they can detect objects as fine as a human hair.
The common bent-wing bat is one of the world’s most widely distributed mammals.
In Australia, it is found from the tropical north to the temperate south coast. At the beginning of summer, pregnant females congregate in their thousands in longestablished nursery caves and give birth to a single young. By March, the young are independent, and adults disperse to their habitual hunting grounds, roosting by day in caves, tunnels, stormwater drains, garden sheds and abandoned buildings.
Microbats use their tail and wings like a baseball glove to catch large insects while
in flight, carrying them back to a favourite feeding site. We sometimes find insect remains on our garage floor, or small, friable, brown scats about 5mm long, showing us that microbats are controlling the insect population in our garden. To encourage microbats and help their conservation, make or buy microbat roosting boxes to give them a safe place to sleep during the day and to hibernate in winter.
Len gardens in the Northern Rivers, New South Wales