BSG Ecology are currently working on several projects in Devon that involve the use of thermal imaging cameras to monitor greater horseshoe bats Rhinolophus ferrumequinum. During a free evening one of our ecologists, Helen Simmons, took the opportunity to visit Berry Head National Nature Reserve & SSSI and film greater horseshoe bats emerging from a known roost. The site is managed by the Torbay Coast and Countryside Trust where she was joined by the Trust’s Countryside Officer, Noel Hughes, who monitors them on a regular basis .
The two videos shown here were recorded on different cameras. The video on the right was recorded using our T650 FLIR camera approximately 12 m from the entrance. The video on the left was filmed using one of our smaller A35 cameras, positioned outside the cave and looking in, approximately 8 m from the entrance.
The greater horseshoe bats in these videos are using visual cues to monitor light levels outside their roost in order to determine if conditions are suitable for emergence – behaviour also termed as ‘light sampling’.
Berry Head Special Scientific Interest (SSSI) is part of the South Hams Special Area of Conservation (SAC). Two of the primary reasons for the designation of the South Hams SAC are ’caves not open to public’ and the population of greater horseshoe bats associated with them, which is thought to be the largest in the UK. South Hams is the only SAC known to support more than 1,000 adult greater horseshoe bats (31% of the UK species population), and also supports the largest known maternity roost for the species in the UK and possibly in Europe (JNCC, 2014), which is why the site is internationally important.
On this occasion 34 greater horseshoe bats were recorded emerging at Berry Head.
Full video available on the BSG Ecology YouTube channel