‘Bats and Castles’ at Fonmon Castle: Learning from the best

On October 16th 2025, members of our ecology team visited Fonmon Castle in South Wales to take part in the Bats in Castles event led by bat expert Richard Crompton. We spent the afternoon exploring the castle and assessing potential bat roosts, discovering around 50 roosting lesser horseshoe bats (Rhinolophus hipposideros), pictured on the left. This is a rare species in the UK so we were very lucky to gain some experience in how to identify them.

In the evening, we carried out an emergence survey outside the cellars using both a Canon XA infrared 50/70 camera and a Guide thermal camera, which provided exceptionally clear footage of bats emerging and re-emerging the building. We also observed serotine (Eptesicus serotinus) and pipistrelle’s (Pipistrellus spp.) foraging nearby, captured using our Pixfra Thermal Monocular. The combination of infrared and thermal technology gave us a detailed and engaging look at bat activity throughout the evening.

The event was highly informative, providing key insights into optimal ways to conduct preliminary roost assessments (PRAs) and dusk emergence surveys. We learned that clothes moth larvae hatch within bat droppings, leaving distinctive patterns to help indicate the whereabouts of bat activity. Lesser horseshoes can be identified by their nose leaf and the way they wrap their wings around themselves when roosting, while their droppings are fine and powdery compared to the coarse droppings of serotines.

Experiences like this help us refine our own survey techniques. By continuing to develop our skills and invest in high-quality equipment, we can provide our clients Get in touch with our ecology team to learn how we can support your project with bat assessments.

 

Follow Us