Batmania: The bats hiding in the backyards of Melbourne
Flying foxes are a common sight on Melbourne’s night sky. Photo credit cskk via Flikr
For two brief years, 1835 to 1837, the capital of Victoria was called “Batmania”. Named after one of its founders, John Batman, Batmania is ironically fitting for a city that is home to a vast array of bat species, however, most Melburnians are unaware that many can be found in their own backyard.
Grey-Headed Flying Foxes, are an iconic species to Melbourne, with most residents being able to identify their silhouette on the nights sky or their unique screech. However, very few Melburnians are aware of their smaller relatives- the microbat. With populations that far out number the flying foxes, there are sixteen species of microbats can be found in the suburbs of Melbourne. The most common species are the Gould’s wattled bat and the Lesser long-eared bat.
Lesser long-eared Bat. Photo Credit Matt Clancy via Wikimedia Commons
As blind as a bat?
Contrary to popular belief, bats are not blind; in fact their vision is about the same as human’s. One of the notable differences between microbats to their larger relatives the megabats, is their use of echolocation to navigate and detect prey. The bats produce a call by forcing air through its vocal chords, which vibrate so rapidly they create a high frequency call. The echolocation call strikes an object, such as an insect, and some of it is bounced back as an echo. The time taken for the echo to return tells the bat how far away the insect is. Some bats have adapted further to use constant frequency ultrasound, that allows them to determine the distance, speed and direction of movement of the insect.
Microbat species have adapted the frequency of their echolocation to the habitat they reside in. Those found in highly cluttered areas with dense vegetation use a lower frequency call as the vegetation interferes with the echolocation call. Whilst species found in environments with low vegetation density, use a high frequency call as the area is so large they do not need to produce the lower frequency calls. As more forests, parkland and high vegetation areas are cleared to make way for human development, those species with low frequency calls are not adapted to these new open areas, therefore the diversity of bat species in these areas are declining. The impact of this change in diversity is so far unknown- but the power of the microbat should not be underestimated.
Nest boxes are a simple way to encourage microbats to your backyard! Photo credit Zorro2212 via Wikimedia Commons
Encouraging microbats into your backyard
Microbats are an important species to have in human environments- with one microbat being able to eat up to 600 mosquitoes an hour. These small creatures can help control insect pests that threaten crops and, in some regions, can even control malaria and other insect-borne diseases. Some species can eat their entire body weight each night! It is predicted that microbats have a stronger positive ecological impact on vegetation health than birds.
Most microbats can be found roosting in tree-hollows. Unfortunately, with increasing urbanisation, tree-hollows are becoming scarce and they are retreating to artificial structures such as sheds and the roof spaces of houses. If you want to reap the benefits of these natural mosquito controllers (no more stinky citronella burners needed!), rather than clearing old tree’s from your property- retain them and plant more trees to create future hollows. A great alternative to tree hollows are nest boxes, which are easy to build and can provide a roosting place for up to 10 years.
NB: To reduce the risk of Australian bat lyssavirus, do not handle bats unless experienced and vaccinated. If you find an injured bat, please contact your local wildlife organisation. If bitten or scratched by a bat please seek immediate medical assistance.
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