Residents near Cannes Reserve, Avalon, will be in for a rude awakening next Monday morning - at 4am.
Pittwater Council hopes to remove hundreds of flying foxes from the reserve to stop their night-time screeching and defecation on homes and cars.
They will use speakers to blast industrial noise at the bats and scare them away. Spotlights and smoke may also be used.
Pittwater Council's natural environment and education manager, Mark Beharrell, said residents had reported problems with the bats for more than five years.
"The residents have issues with noise, there's odours, houses with bats defecating on them. They're concerned about house values and problems renting out their homes," he said.
After chopping down trees and creating buffer zones in the area, Mr Beharrell said the noisy dispersal attempt was the council's last option.
The council has budgeted a maximum of $120,000 for the program, a figure that includes maintenance and repeat attempts to disperse the bats if the first one fails.
Removing flying foxes through the use of noise and light is a tactic that has seen mixed results across Australia. Some experts say it isn't effective, and Pittwater Council recognises there's a chance the program won't work.
"They will come back, and then we bounce them off again. We can only do that so many times. There's mixed views on it. People will tell you it will and won't work," Mr Beharrell said.
UWS flying fox expert Dr Justin Welbergen said flying fox dispersal efforts were usually unsuccessful.
"Noise, smoke or light, they may get rid of the flying foxes for a little while but in all cases they've all come back repeatedly and in virtually all cases they will come back so often that people will give up," he said.
The number of flying foxes in the Cannes Reserve fluctuates. At the moment, there are about 250 bats, though this time last year there were 3500. Bats from Sydney can roam as far north as Rockhampton and far south as Melbourne and don't have belong to a single colony, Dr Welbergen said.
He said removing the bats from the reserve was not the answer.
"I've seen what these people go through and understand where they're coming from. But education and financial support can help. Double glaze the windows to reduce noise, modify the vegetation so flying foxes are not roosting directly above houses," he said.
The dispersal has been licensed by the NSW Office of Environment and Heritage.
