Marsh Fritillary Population Monitoring 

The marsh fritillary butterfly is usually found in damp, heathy grasslands, where it is reliant on Devil’s bit scabious as its sole larval food plant. 

Habitat loss and fragmentation have caused declines across its range, and the UK is now considered one of the last strongholds for remaining populations.

Marsh fritillaries are also protected under both UK and European law. We previously monitored some of the Cornish marsh fritillary populations through butterfly counts during the flight period and through larval web counts during the development stage.

During the larval web counts, thermal imaging cameras used in conjunction with drones enabled us to detect clusters of larvae through their heat signatures, so we can more accurately estimate population sizes.

This project is currently on pause on our side, though monitoring and habitat management for the marsh fritillary is still ongoing at Trelusback Farm.