Bats are our backyard friends and it would be ghoulish to think otherwise. We caught up with Joanna Haddock, School of Life and Environmental Sciences PhD candidate, to learn more about these misunderstood little creatures.
"Australia has over ninety bats species and around twenty reside in Sydney. Three of these species are the ones you will be use to seeing quite a lot – they are the flying foxes, and this species eat fruit.
"What you may not know is that over seventeen species in Sydney are tiny insectivorous bats – that is, bats that eat insects. These species can be as small as 4 grams fully grown- weighing less than a 10 cent coin. These amazing little critters roost under tree bark, in hollows, under bridges and wooden docks, and some even roost in caves. They are eutherian mammals which means that they reproduce very much like us – pregnancy, birth and lactation," says Joanna.
Insect-eating bats use echolocation to navigate and hunt - the bats emit a series of high pitch clicks and listen to the echoes to work out where objects are. Amazingly, each species has evolved a slightly different tactic to catching their prey, and bat researchers can tell, with the help of some high frequency bat recorders, what species are flying overhead at any point during the night. All this high frequency noise is going on above your head every night in Sydney and you would never know.
This Halloween we focus on some of Sydney’s microbats to discover more about these fascinating mammals:
Australian Fishing Bat (Myotis macropus)
While you sleep at night, the Myotis macropus is out fishing on Sydney Harbour for tiny fish and insects. Also known as the Large-footed Myotis because they have disproportionally long toes compared to their body size. Using these long toes they reach out and trawl the surface of the water to catch their tiny prey. The Australian Fishing Bat live in colonies close to the waters edge in storm water drains, under bridges and even under jetties around the harbour.
Greater Broad-nose Bat (Scoteanax rueppellii)
This is one of the larger microbat species in Australia measuring in at an average of 9.5cm. This species can be recorded across many parts of Western Sydney, and found in a variety of habitats from woodlands, rainforest and buildings. This bat species concentrates on aerial foraging, it eats its prey in flight, meaning it can be airborne for hours at a time. It is an avid insect eater, with beetles, moths and commonly cockroaches on the menu, a good reason to encourage them into your urban neighbourhood. The biggest challenges facing the Broad-nose Bat are habitat loss and tree hollow competition from urban birds like Indian Minors.
Eastern Long-eared Bat (Nyctophilus gouldi)
One of our resident long-eared bat species has a distinctive look due to its ears characteristically being larger than its head. This bat uses its huge ears to listen for rustles of insects scuttling around on the floor. The long-eared bat can sometimes land on the floor to catch its prey, and loves eating beetles. These species are particularly sensitive to light pollution, and Sydney’s long-eared bats live in larger dark bushland patches to avoid roads and streetlights. Cats also often catch this species while they are on the floor so please remember to keep your cat locked inside at night time.
Some bat species are widespread across Sydney, and have seemed to adjust to life in the city. Wherever you live in Sydney, chances are you live within walking distance of a bat roost. However, there are other bats that are not doing as well. “One of the biggest challenges for insect-eating bats in cities,” says Joanna, “is finding connected and lush native bushland, unpolluted by artificial light and noise.” Bushland is important for a lot of different types of biodiversity, and making sure that we have forest corridors across our cities is important so that our native animals can move around without coming across humans, roads and streetlights.