They disturb the peace, smell and leave droppings on cars and pavements, but despite attempts to clear various Sydney suburbs of flying foxes, the battle has little chance of waning, according to an ecosystem scientist.
While bat population numbers are decreasing, the number of roosting sites or camps in Sydney have sharply increased as the animals continue to move into urban areas in search of food.
"The number of flying fox camps have increased from seven to 20 in the past five years," Peggy Eby, lecturer at the UNSW Centre for Ecosystem Science, said.
"When the animals don't have enough food, they've established new camps."
Flying foxes gather together in groups and leave their young behind as the adults search for food.
PHOTO: Peggy Eby said trying to remove flying foxes from one site simply shifted the problem to a neighbouring area.(Supplied: Peggy Eby)
Ms Eby said more camps across Sydney had reduced the distance the bats have to fly between their resting place during the day and eating sites at night.
"Part of the reason might be is that people water their gardens during droughts, and we've had some dry spells, so the people water their gardens and the eucalypt trees might be flowering and fruiting more frequently," she said.
"There's greater diversity of trees because we've planted this artificially diverse woodland in our gardens and along our streetscape.
"It just provides them with a more regular food supply."
Shifting the problem
Ms Eby said the first camps to form were in the Sydney Royal Botanic Gardens in the late 1980s.
The gardens attempted to move the bats in 2010 by blaring loud sounds to scare them off.
Flying foxes have also plagued suburbs like Gordon, Singleton and Batemans Bay, where councils and residents have attempted to move the roosting camps with a similar technique, as well as removing vegetation.
Singleton visitor Jane told 702 ABC Sydney that Burdekin Park was filled with dead trees and looked like "an atomic bomb had hit it" due to the flying foxes.
While resident Jessie said the bats had moved into the city area after the forest on the outskirts of the suburb were bulldozed about 15 years ago.
Ms Eby said that dispersing the bats simply moved the problem "to someone else's backyard".
She said they simply shift to another canopy of trees close by and may eventually return to the original site.
"We don't know how to manage them in a low risk, low cost way," she said.
"We can prevent the animals from roosting in a particular spot, but we can't control where they are going."
Despite having studied flying foxes for the past 25 years, Ms Eby said there was still no solution to controlling where the nomadic animals roosted.
When asked whether people could do anything about them, she answered definitively: "No".
"We need to reduce conflict for the community, not just for a particular local site," Ms Eby said.
"We've been doing this for 200 years — it's about time we we researched the best way to control them."