FOR the first time in weeks the trees behind Hamilton Oval were bat free after the second dose of scare tactics was delivered early yesterday morning.

The bats have all moved further up the river and are now located behind Warwick State High School's agriculture centre.

While it might appear to be working at the moment flying fox expert Dr Jon Luly, from James Cook University's Earth and Environmental Sciences Unit, said moving bats on was often unsuccessful.

"The lesson learned from moving on flying fox colonies is that it is a really bad idea," he said.

"It can cost a lot; there is no guarantee of success, though people often think they have successfully moved the bats when they have, in reality moved on due to drying up of food source.

"The relocated bats often end up in places that are less desirable than the ones they were displaced from in the first place."

Dr Luly said it was hard to determine exactly why the little red flying foxes had picked to roost at that exact location.

"They are extra mobile, ranging over many kilometres foraging and to follow the seasonal pulse of flowering of their food trees, which are principally eucalypts and paper barks," he said.

"They are often found in extremely large colonies which hang around for a period but move on when food supplies are exhausted.

"They usually roost near water in large trees, often where there is some humidity or access to a drinking site, such as a river or lake.

"Need reasonably large trees to support the weight of the clusters of bats that hang close together, probably for protection from the elements."

Dr Luly said it as the right time of year for the bats to be giving birth.

"Typically this happens around April/May," Dr Luly said.

"Bats carry their young with them while they fly at first as their young can't fly.

"Baby bats are put into crèches and if the mothers were scared off lots of baby bats would be left to starve.

"Which is unacceptable from a cruelty point of view."

Warwick resident Warren Webster said he had his fingers crossed the bats would continue moving away.

"We live out near the hospital and we sit here at 6.30pm and watch them moving to wherever they are going," he said.

"They are landing in the trees around our home and we have taken our measures to stop them. Including lights and horns.

Mr Webster said even if they are able to move the bats on they will just return next year. Dr Luly said this was a possibility.