Bat hibernacula

WW2 Defences protecting our bats and our country!

FWAG East recently took up the unusual task of redesigning a disused World War II pillbox for conversion to a bat hibernacula. The pillbox, located at College Farm near Duxford in Cambridgeshire, is one of a series of small, fortified structures that were constructed across East Anglia as part of the British anti-invasion preparations.

Natural bat hibernation sites such as caves and deep rock and tree fissures are characterised by thick walls that buffer their interior spaces from fluctuating ambient winter temperature and humidity. The very nature of a pillbox, with walls built to shellproof standard of around 1 metre thick, means that it can easily mimic these conditions.


Bat hibernacula

The habitat potential of the pillbox was highlighted during College Farm’s entry into the Higher Level Stewardship (HLS) scheme in 2013, particularly because although South Cambs provides a reasonable number of good breeding sites for bats, there are fewer hibernation opportunities. The pillbox could potentially attract species such as pipistrelle, brown long-eared and Daubenton’s.

The conversion of the pillbox will ensure that the original fabric of this historic building will remain intact, with a few additions made.

The gun slots will be almost entirely blocked up to leave a very narrow entry point, whilst the smooth internal walls will be fitted with wooden batons on which to fix protruding tiles for bats to crawl behind for their hibernation period.

This simple project is one that could be easily replicated on other farms across the region where these small, unassuming buildings are occasionally found lying in disrepair. It is worth noting that in Britain all bat species and their roosts are legally protected so if you have reason to believe that your pillbox is already in use by bats, it should be left completely undisturbed. If you would like further advice on how you could covert a pillbox to a bat hibernacula then please do get in touch with us at the FWAG East office.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

FWAG East is part of the FWAG Association: FWAG East CIC is a limited company registered in England. Registered No: 08776388. Thanks to Chris Loades for images: