Bats often roost in barns and a simple visual check is not sufficient to discover roosting locations. We recently carried out a Preliminary Roost Assessment on a Barn in Hertfordshire. It was an old listed barn with numerous mortise and tenon joints. Many of these had small gaps and we had to spend several hours investigating each one with an endoscope. Above shows a roosting Barbabstelle Bat within a small crevice within an oak beam, several meters high. A search from ground level didn’t uncover the bat, it wasn’t until the feature was endoscoped that the bat was discovered. The use of an endoscope to survey for bats requires a Class 2 bat licence.
This joint in the bracing beam had a tiny opening, only around 10mm at the entrance, but this went back about 30cm and opened up to a larger void. Again, a ground level search with a torch is not sufficient to discover the concealed bat. Barns are a very different structure to a residential house and as such a different approach is needed when surveying to avoid roosting bats being missed.