‘Living lawmowers’: How hungry hairy Hungarian hogs will help save the UK’s most endangered butterfly

Yes, you read that headline correctly. Pigs and cows will help Butterfly Conservation maintain one of the last remaining breeding spots for the High Brown Fritillary butterfly.

Hairy pigs from Hungary have descended upon Exmoor in a bid to boost the population of the UK’s most endangered butterfly, the High Brown Fritillary. The pigs, known as Mangalitsa, are being used to manage the habitat where the butterflies breed, by devouring and destroying high-growing trees and shrubs that would otherwise overwhelm the south-facing bracken covered slopes. 

The High Brown Fritillary, resting on a nice fern. Credit Iain H Leach

The High Brown Fritillary, so named by the Society of Aurelians, is one of the largest butterfly species in the UK. However, its population has declined by 65% since 1978 and is now found in just three locations in England, one of which is the sunny Heddon Valley near Barnstaple.

As part of a new project by Butterfly Conservation, The hairy hogs are being combined with English Longhorn cattle owned by the National Trust to create a small army of living lawnmowers. ‘This is an incredibly exciting project and working with the National Trust is very rewarding,’ says Butterfly Conservation project officer Ellie Wyatt. ‘The trust have been working with the pigs for a couple of years and noticed how their rootling actions benefited the soil and encouraged violets to germinate, so it’s great to continue this work to help save the High Brown Fritillary.’

National Trust ranger Finley Binns and Butterfly Conservation project officer Ellie Wyatt withone of the Mangalista pigs. Credit: Savannah Jones

Recommended videos for you

‘The Longhorn cattle are also gorgeous and look majestic in the landscape and I’m looking forward to seeing the trails they and the pigs make through the bracken and seeing if violets spring up in these paths,’ she added.

The ‘innovative’ project secured a £228,000 Species Recovery Grant from Natural England last year, which will not only pay for the pigs, but also fencing to make sure that the mowers stay on target during the project. The team are also collecting tiny seeds from Common Dog-violets — the primary source of food for the High Brown caterpillars — and germinating new plants in an off-site nursery. It’s hoped these new plants could be put elsewhere, boosting the butterflies breeding range.

Mangalitsa pig having a rest after a hard day’s site management. Credit: Savannah Jones

‘Collaborating with butterfly conservation has allowed us to do some exciting and much needed work in our woodlands that will benefit the high brown fritillary as well as many other species,’ says Mathieu Burtschell, National Trust ranger for West Exmoor. ‘Most of our wooded valleys on West Exmoor were exploited for oak timber and were cyclically clear felled. This industrial exploitation ended about 100 years ago, and the oak trees were allowed to get away. The issue we now have is that most of the trees are the same species, the same age, and featureless.’

Some of the English Longhorn cattle also on site. Credit: Savannah Jones

Butterfly Conservation’s work at Heddon Valley has already yielded success, the charity says, with a 20-year-high in the butterfly population recorded at the site in 2022. The charity has also identified 10 other National Trust sites where new colonies of High Brown Fritillary could establish, and is now appealing for donations to do so.