Did you know that many of our microbat species are hollow dependent? This means that they live during the daylight hours inside the hollows of trees, sometimes even hollow branches.
As you can imagine there are many other animals who also look for hollow trees to live in including birds, possums and gliders. Sadly however these old trees are disappearing due to land clearing. Councils are also cutting hollow limbs from trees as they are presumed to pose a danger to the public in parks and reserves. Unfortunately it can take decades, if not hundreds of years, for a tree to develop a hollow suitable for some inhabitants.
On one occasion a small colony of free tail bats Mormopterus loriae that were living in a branch with a 15cm diameter had to be rescued. It had been hollowed out by termites and was a perfect home with many little twists and crevices for microbats to live in.
Unfortunately, some well meaning locals thought the tree needed a prune as they posed a danger if these branches were to fall down on to the road. The local council which authorised this to be done was very surprised that local wildlife became displaced as a result. The branch with the remaining colony of microbats was taken to a Bat Rescue member, who provided them with a nest box and the colony in their new home were relocated soon after.
This is why artificial roost sites are so important as they often provide that alternative, and microbats do use them. For a bat house design that really works see Hollow Log Homes.
Bats are also known to use roofs and walls in dwellings if they cannot find a suitable hollow. If home owners are unhappy with their tiny boarders there are humane ways to exclude them from homes and provide alternative roost sites. For those seeking such a solution, information is provided in this document: Little Bats in the Wall.
Please note that in Australia the young of microbats are born in late spring and remain with their mothers until the end of January. Any attempt at gentle bat eviction should be made in Autumn, or at least after February and before June when it can be certain that the young are fully independent.
Here are links to some easy-to-build Microbat houses:
1 - Batflat 1
2 - Batflat 2
3 - Batflat 3
4 - Batflat 4