Marsh fritillary, Ennerdale, Lake District

A Marsh Fritillary rests on a Ranger's hand, Ennerdale, Lake District

One of Europe’s most protected butterflies is marching across one Lake District valley – thanks to innovative grazing and warm weather.

Marsh fritillary numbers have dwindled since the end of World War Two, as farming became more intensive. In the 1970s the butterflies disappeared completely from Ennerdale, a valley that boasts the Lake District’s most westerly lake.

But the marsh fritillary is bouncing back, following a conservation programme that has seen the butterfly reintroduced to several sites across the valley. 

At Mireside Farm, rangers, volunteers and farmer Judith Weston have worked together to boost butterfly numbers on 10 acres of wet grassland beside Ennerdale Water.

Farmer Judith Weston, who grew up on the traditional sheep farm, said: ‘We were one of the sites that were chosen for the first reintroduction. We’ve got land here that’s quite marshy and it’s full of common orchids.’

We couldn't do it without partners like Ennerdale farmer, Judith
Ranger and farmer look for Marsh Fritillary butterflies in Ennerdale, Cumbria
We couldn't do it without partners like Ennerdale farmer, Judith

‘We cut the rushes back with a powered scythe,’ said National Trust ranger Chris Gomersall. ‘We try to do about a fifth of the fields at a time – always in autumn, so that come the spring there’s much more light getting to the ground flora.’

The marsh fritillaries rely on the devils bit scabious food plant, which is booming at Mireside. The number of webs spun by the butterfly larvae have almost doubled since 2010.

The butterflies are spreading across the Ennerdale valley, with conservationists putting the success down to good habitat management, light cattle grazing, and good weather.

Rachel Oakley, from the Wild Ennerdale partnership said: ‘The cattle grazing is helping to create a mosaic of habitats across the valley, enabling both the butterfly and its food-plant to expand.

‘The middle valley fields and the river Liza corridor are seeing butterfly numbers increase and migrate eastwards up the valley. It’s great news for everyone involved in helping this lovely butterfly have a bright future in Ennerdale.’

We’re working with tenant farmer Richard Maxwell and grazier Richard Taylor to promote the marsh fritillary at the head of Ennerdale valley and Longmoor Common.