Albury Council is preparing to serve them with an eviction notice and would see them off with a bang.

The council has applied for a permit from the NSW Office of Environment and Heritage to move on the colony, whose population has swelled to more than 1000.

That’s more than five times the number that arrived in the trees at the start of summer.

It is unclear when the move will start, as the council awaits a decision on its application.

Parks and recreation team leader David Armstrong said once the permit was received, as anticipated, it could take about four weeks for the entire colony to leave.

“It is still possible they will leave of their own accord before we get that permit, if it gets too cold,” Mr Armstrong said.

The permit would be valid until next year, so if more arrive by summer the council would still be allowed to move them on.

While the bats were something of a novelty when the first 200 arrived, their increasing population has been cause for alarm.

Mr Armstrong said aside from forcing the closure of the children’s garden, the bats had stripped foliage from some trees, though they would likely recover.

“We could tolerate that in some of the trees but they have since got in to the more significant ones, like the kauri tree, and we really want to protect those,” he said.

Mr Armstrong said the council had consulted with experts from Melbourne’s botanic gardens, which has successfully moved on bat colonies in the past.

“Mostly, it would involve making a lot of noise to make the area uncomfortable for them, especially in the early morning and evening,” he said.

“It could be mechanical noise like whipper-snippers or chainsaws, or things like drumming, or banging on garbage can lids.”