Marsh Fritillary Surveys
The marsh fritillary is a threatened species in the UK and across Europe. It is listed in Section 7 of the Environment (Wales) Act 2016, a species of principal importance under the NERC Act in England and is fully protected under the Wildlife and Countryside Act 1981 (as amended).
The main foodplant of the marsh fritillary is Devil's-bit scabious in habitats such as tussocky grassland, chalk grassland and coastal grassland. The species requires extensive habitat networks and habitat fragmentation has contributed to its decline across the UK.
Suitable habitat for marsh fritillary may be observed during Preliminary Ecological Assessments and specific habitat surveys should be undertaken between May and November when devil's-bit scabious is growing. If suitable habitat is observed then further survey may be recommended if habitat will be affected by development.
The adult butterflies are on the wing from May to July and survey visits can be undertaken between mid-morning and mid-afternoon when conditions are warm and sunny.
A survey of larval webs is the most reliable method of assessing populations of marsh fritillary and can be carried out between late August and early October.
