As they take wing to the night’s skies thousands at a time, filling the air with raucous screeching and leathery flapping wings, the sight is not one you’d easily forget. While many think of bats as living in caves or forests, eastern grey-headed flying-foxes have taken up permanent residence in major cities across eastern Australia for the past 20 years.

Victoria’s most well-known colonies are found in Melbourne, Geelong and in Bendigo. Yearly migration cycles of the bats have them travelling as far as Queensland and Adelaide.

Despite settling into urban environments, bats are still wild animals. Interaction with the public is inevitable, but, as they are a vulnerable and protected species, cities must find ways to live alongside them and work with the bats in mind.

Geelong’s Eastern Park, located southwest of Corio Bay, homes a permanent colony. This colony is thought to have originated from a relocation of bats from Melbourne’s Botanical Gardens in 2003.

Steve Smithyman, a Conservation Reserves team member from the City of Greater Geelong, tells upstart about the public’s relationship with the bats.

“Our biggest issue comes from when our bats fly out at night to feed … I’ve been told they go to the toilet about every 20 minutes … We get a few complaints from stuff like that, where the bats are pooping on people’s paths, on their walls, on their washing,” he says.

“So, we run an education program that says the bats are going to keep coming over because they’re going out to a food source, so if you can, just adjust to them. Don’t put your washing out at night, bring it out at day.”

Community events also run in and around Eastern Park, and it’s Smithyman’s job to make sure the events are run with the bats’ welfare in mind.

“We’ll have the Million Paws Walk, we’ve got park runs, we’ve got community days with barbeques. Colour runs… We discuss it with them and then we say, ‘can you not do the colour thing [near the bats]’… They still get to do it; we just make sure it’s not near the bats,” he says.

Smithyman notes that disturbances can be more detrimental for a colony than just a momentary unsettling.

“Bats can be disturbed to an extent that they’ll just fly off and leave the colony and may not come back … [Experts] also think that potentially if there’s a lot of smaller disturbances, like an accumulation, that might also trigger something like that too,” he says.

Geelong is planning to install a tree-mounted sprinkler system in coming months to help minimise the risk of heat stress to the colony during summer.

A couple hundred kilometres north of Geelong, the central Victorian city of Bendigo has its own permanent grey-headed flying-fox colony.

From near-misses with hospital helicopters to spreading across the entirety of the park mid-year, their bat population has been contentious with locals for some time.

The colony made the area its residence in 2010 after severe weather in Queensland forced them to migrate south, where they have since remained a permanent presence in Rosalind Park.

Bat numbers expand to upwards of 38,000 bats in autumn and winter, where they spread beyond their usual camp in the park’s fernery corner and take up all of Rosalind’s trees. Bendigo City Council uses a ratepayer-funded cleaning crew to keep the space clean throughout the year.

Bendigo’s Department of Energy, Environment and Climate Action (DEECA) branch also works closely with the city to monitor the colony. They run surveys of bat population numbers for the National Flying-Fox Monitoring Program, and provide advice to the community on how to manage flying-foxes.

Though some locals still harbour concerns about living so closely with bats. Simone Egger, DEECA’s Media and Communications Program Manager, relayed to upstart some local community sentiments.

“Grey-headed Flying-foxes can cause concern for community members due to reasons such as noise, odour, impacts on trees and perceived disease risk,” she says.

While bats can carry lyssavirus, less than five percent of the flying-fox population are said to be infected, and it only spreads through their saliva. If you don’t touch a bat, they can’t infect you.

“Grey-headed Flying-foxes are also valued in the community, in part due to their role as a pollinator and seed disperser in Australian forests,” Egger says.

Back to Victoria’s capital, Yarra Bend Park, located in the Melbourne suburb of Kew, is home to Victoria’s largest permanent colony.

Originally settling into the Melbourne Botanical Gardens in 1986, a relocation plan enacted in 2003 saw the bats dispersed, and Yarra Bend Park was one location they fled to. The park hosts upwards of 30,000 bats in the summer, with the colony dropping to 6,000 by winter as most of them migrate north.

Though the relocation satisfied the bats and surrounding parkland, locals found that summer months were particularly trying for the species. The bats can’t self-regulate temperature, so Parks Victoria rangers would historically find instances of bats dying or suffering from heat stress.

As of February 2023, rangers and Zoos Victoria experts installed a system of sprinklers across three hectares of parkland trees to help avoid heat-related bat deaths.

Though the efforts of each city are separate and specific to their own circumstances, they all serve to help keep the bat colonies sustainable, the parks that house them flourishing, and have as little impact on the surrounding urban environment as possible.

Photo: Grey-headed Flying-foxes by Rob available HERE and used under a Creative Commons license. This image has not been modified.