A night of moth recording reveals a rare resident of a Welsh fen

Three moth traps left overnight at a Welsh nature reserve have revealed something its recorders had never found there before: the scarce bog grass-moth.

Conservationists counted 19 of the moths at Cors Geirch, on the Llŷn peninsula, among 446 moths representing 91 species. The summer survey has now been reported by Natural Resources Wales and the BBC.

The find helps explain why this wet ground matters. The moth’s caterpillars feed on sedges, plants supported by the fen’s conditions. Local contractors and volunteers have been opening up wet, calcium-rich areas through the Natur am Byth conservation programme.

The specialist UKMoths guide says adults usually fly in July and August and are attracted to light, making summer night surveys a useful way to find them.

A first record does not prove the moth has just arrived, or that its numbers are increasing.

It does give the people caring for the reserve a clearer picture of what lives there. Keeping these small, specialised habitats in good condition gives their easily overlooked residents a place to persist.

Sources

• BBC — the newly reported local discovery
• Natural Resources Wales — survey counts and fen management
• UKMoths — flight season, light attraction and larval food