“Bats are natural aerial acrobats! While most bats catch insects in their mouths, they can also catch insects in their wing membrane, flick them into the tail membrane, and then grab them with their mouth, all while in flight.” (from Australasian Bat Society, “Bats: Fascinating Creatures of the Night” brochure)
The Regenerators participated in the 2013 ACT Batwatch Program, when five bat species were recorded living on Red Hill. These were:
- Gould’s wattled bat (Chalinolobus gouldii)
- White-striped mastiff bat (Tadarida australis)
- Little forest bat (Vespadelus vulturnus)
- Chocolate wattled bat (Chalinolobus morio)
- East coast mastiff bat (Mormopterus ‘species 2’)
The results of the survey can be seen here
From the Friends of Jerrabomberra Wetlands:
Many people came to the Bat Talk on Thurs afternoon of March 20th 2015, when Dr Doug Mills, senior researcher with the NSW National Parks and Wildlife Service, talked to us about the fascinating world of microbats, and a bit about megabats (flying foxes). Microbats use echolocation to find food and navigate. They are very small, come out at dusk or later, and there is only one species that calls at a frequency we can hear (below 20 kHz), the White-striped Freetail Bat, so we can’t ever hear the others. Most of us are completely unaware of them. No wonder we overlook one of the most populous groups of native mammals that shares our suburbs, which is also the 4th most populous group of native mammals in Australia.
Bats play a vital role in the health of ecosystems and we have around 18 species of microbats in the ACT. Jerra Wetlands is likely to be a hotspot for them because there are many more insects over water, as well as around mature trees, and there is a variety of habitats. Microbats eat 25-50% of their body weight in insects a night (???). Doug told us about US farmers using bat boxes to support large colonies of microbats that eat insects in their orchards every night, saving them billions of dollars in reduced fruit damage and pesticide use.
The following night, Doug, ecologist Jane Roberts, and some dedicated and enthusiastic bat experts, led one of three groups on a Bat Walk through Jerra Wetlands, when we surveyed for microbat species. It was a surprisingly cool and windy night so bat numbers were down considerably on the “recce” they did 3 weeks before, but there were still about 5 species recorded, and we counted around 30 Grey-headed Flying-foxes passing overhead whilst we surveyed.
The surveying was done using “bat detectors”, hand-held ultrasonic recorders which convert the bats’ high frequency sounds to a range we can hear, as well as showing passing sound pulses on the screen and recording the sounds so they can be analysed later. Microbat “calls” are more difficult to identify and distinguish than frog calls, partly because they are affected by distance and flying angle in relation to the bat detector, and by doppler effect. The microbat species identified included long-eared, forest and wattled bats, including Gould’s Wattled Bat.
Though some microbat species do well in urban environments, some are disturbed by bright lights, and many have declining habitats. I am hoping that we can muster the expertise, equipment and interest to continue regular bat surveys into the future, which Friends would be keen to take part in. Thank you to the Australasian Bat Society for helping make the bat talk and bat night a great success, and for lots of great take-home information for the participants. If you want to find out more about bats, there are some great fact sheets available on the Australasian Bat Society website, including information on how we can help our neighbourhood bats. For more on recording microbat sounds, there is some interesting information here that (despite being a UK website) illustrates some of the sound characteristics and issues Doug covered over the two bat sessions.