Tore Christian Michaelsen watched with growing satisfaction as a stream of bats dropped down out of the bat house on the side of a farmer's barn. More than 75 of the little soprano pipistrelles emerged to fly off into the evening sky. A quick check revealed a few adult still inside the bat box, as well as a large number of pipistrelle pups clustered high inside one of the five roosting chambers.
A maternity colony in a bat box was virtually unheard of in western Norway six years ago. But that has changed dramatically thanks to the pioneering bat-house work of the Norwegian Zoological Society Bat Group, with support from a Bat Conservation International Global Grassroots Conservation Fund grant in 2005.
For the first time in Norway, Michaelsen and the NZS Bat Group introduced and tested large bat boxes that follow BCI's recommendations and building plans. Their results won both public and government support for these larger alternative roosts, which have proven far more effective than the smaller bat boxes that had been typical.
The need for bat-friendly bat boxes in Norway is great. Several Norwegian bat species use buildings, including people's homes, as roosts, and that often stirs homeowner complaints. Although the main issue is often a lack of knowledge and unjustified fears, noise and odor can create real problems in some buildings.
Until recently, the only option to excluding bats from buildings was to seal off all potential access points. In most cases, though, the homeless bats simply moved into other buildings. And that's where these new bat boxes are making a difference.
After noting the success of BCI-style bat houses around North America, the group requested – and received – a Global Grassroots grant to launch a pilot project to install and test the impact of these bat houses in western Norway.
The team needed to determine whether bats would use these BCI-style bat houses at northern latitudes in Europe, and then whether bats would voluntarily move out of buildings and into large bat boxes without actually having to exclude them from their current roosts.
By the second year of the effort, seven of the eight installed houses were occupied, and one provided a maternity roost for at least 40 northern bats, with only 10 bats still using their original roost inside a nearby building. In 2007, the results were so promising that the Norwegian Directorate for Nature Management and local agencies provided funds to install and monitor seven more bat boxes.
By 2011, most of the boxes are occupied, mostly by soprano pipistrelles. The largest-known maternity roost in this northern region is now in a five-chamber BCI bat box. Almost 300 female bats and an unknown number of pups now have a safe roost mounted on a barn. Their original roost in an adjacent building is still available, but the pipistrelles use only the bat box.
With the success of the pilot project, Michaelsen said, the bat-box program has now expanded with full funding through the National Action Plan for Bats. BCI-type bat boxes are being produced by a small Norwegian company and distributed free of charge to homeowners throughout southern and central Norway.
Bats around the region can look forward to comfortable new homes in the future.
BCI Members can read the whole story of the Bat Boxes of Norway in the Fall 2011 issue of BATS magazine. To help BCI support critical bat-conservation efforts like this one around the world, please go to www.batcon.org/donate.