Otter Monitoring and Habitat Connectivity Across the River Thaw Catchment

Overview: 

Wildwood Ecology was commissioned by the Restore the Thaw Landscape Project, in partnership with Vale of Glamorgan Council, to undertake an otter monitoring programme across the River Thaw catchment. Using strategically deployed wildlife cameras, the project aimed to improve understanding of otter movement and bridge usage throughout the landscape.

The findings will help inform future habitat connectivity and mitigation measures designed to support safer movement for otters and other wildlife species across the Vale of Glamorgan. The project also contributed valuable ecological data in response to concerns surrounding declining otter populations identified through recent Natural Resources Wales (NRW) monitoring.

Challenge

The project presented several logistical and technical challenges. Camera locations needed to provide clear views of potential otter crossing points while remaining discreet to minimise the risk of theft or tampering. Access arrangements also required careful coordination across multiple private landholdings throughout the catchment.

Technical issues with one camera deployment created additional challenges, requiring equipment replacement and adaptive field management to maintain survey continuity. The project also relied on efficient scheduling and robust data management procedures to ensure cameras, SD cards and footage from multiple locations remained organised across consecutive deployments.

Finally, while recorded footage of otters actively using bridge structures was relatively limited, sufficient evidence was gathered to identify key movement corridors and develop practical recommendations to improve habitat connectivity and reduce road mortality risks.

Approach

Wildwood Ecology designed and delivered a two-phase camera monitoring programme across the River Thaw catchment, with 14 locations surveyed during Deployment A and a further 12 locations surveyed during Deployment B. Cameras were installed for six-week periods, with interim visits undertaken to replace batteries and SD cards and to ensure continued functionality.

Camera traps were strategically positioned at bridge crossings, culverts and watercourse pinch points to maximise the likelihood of detecting otter activity and wider wildlife movement. Equipment was mounted discreetly on existing structures or stakes approximately 30–50cm above ground level, with positioning carefully selected to optimise field of view while minimising disturbance.

Captured footage was reviewed and analysed to identify otter activity and assess how crossing structures were being used within the wider landscape. The findings were then used to inform targeted recommendations aimed at improving habitat connectivity and reducing wildlife road mortality risks across the catchment.