Bats MUST be able to fly extremely well before being released back into the wild.
They must be eating well.
Artificial roost boxes are provided for those bats that are to be in care for a longer period so when the time comes for release, their new/alternative home can be fixed to a nice tall tree. These boxes need to be fixed at 4 metres or more to avoid predation by cats and foxes. They require a clear flight path.
Case Study: Western Broad-nosed Bat
This is a photograph of a Western Broad-nosed Bat (Scotorepens balstoni), juvenile female weighing just 5 grams!
Found exposed in the daylight on the ground. Tiny hole in wing membrane but otherwise quite healthy but still a youngster.
She was in care for two weeks before being released on a delightfully warm night with plenty of insects and century-old Eucalyptus camaldulensis (River Red Gum) hollows to choose from.
She flew away into the night. Sweet little one!