Rare heath fritillary butterflies surge in number on Exmoor after sunny spring

The heath fritillary was almost extinct in Britain in the early 1980s, but targeted conservation work has brought it back from the brink. Photograph: National Trust Images

The combination of sunny spring weather and habitat improved by a herd of red Devon cattle has led to a surge in numbers of one of the UK’s rarest butterflies on moorland in the English west country.

As well as increasing in established pockets on Exmoor, the heath fritillary is spreading to new areas, which experts say is highly unusual.