New population of rare butterfly found in Kent

A new population of one of the UK's rarest butterflies has been discovered in Kent.

Heath Fritillary, which was considered to be on the brink of extirpation in Britain in the 1970s, has been observed at the Woodland Trust's Victory Wood near Whitstable – the result of a restoration project at the site, which has helped wildlife return to the area.

The original ancient woodland on the Victory Wood site was felled and ploughed up between the 1950s and 1970s and later earmarked as a potential landfill site. It was saved by the Woodland Trust in 2004 and became a flagship site for the Trafalgar Woods Project to commemorate the bicentenary of the Battle of Trafalgar in 1805.

The Woodland Trust has now restored this valuable element in a chain of woodlands, re-connecting it to surviving ancient woodland fragments to both the east and west. This extensive site overlooks the Thames Estuary and is open to the public.

Heath Fritillary remains one of Britain's rarest butterflies, so the discovery of a new population is a big boost for its conservation (Mark Rutter).

Claire Inglis, the Woodland Trust's Site Manager at Victory Wood said: "The discovery of Heath Fritillary is a wonderful find and comes after many years of hard work from volunteers and members of the Trust to restore the site to some of its former glory.

"We planted large areas of woodland and ensured buffer zones lined the adjacent ancient woodland areas to encourage natural regeneration. This planting/regeneration in buffer zones, along with maintaining wide rides (trackways), has all been important for the establishment of these special species.

"This rare butterfly returning shows the importance of this work and we hope to discover more species colonising the site in the months and years to come."

Butterfly Conservation has been studying and working to conserve Heath Fritillary since the early 1980s. At that time the species was thought by many to be on the brink of extinction from the UK. Forty years later is now thriving in Kent, even if its wider UK range remains limited to four populations.

Regional Conservation Manager for Butterfly Conservation, Steve Wheatley, said: "The return of the Heath Fritillary to Victory Wood is the result of an intricate chain of actions that began when the Woodland Trust started their restoration project.

"The female Heath Fritillary needs to find the plant Common Cow-wheat to lay eggs for the next generation of caterpillars to feed upon. Cow-wheat is slow to spread, relying on Wood Ants to carry the seeds to new areas. In order for cow-wheat to grow, it needs to take carbon and minerals from the roots of nearby oaks. This relationship between the ants, the trees, the flower, and the butterfly is just magical, and none of this could have happened without the vision of the Woodland Trust."

Woodland Trust staff alerted Butterfly Conservation to the presence of the Wood Ants and subsequent reappearance of cow-wheat. In summer 2020 Butterfly Conservation's Steve Wheatley surveyed the cow-wheat and determined that it was now becoming sufficiently abundant to support the butterfly. Several Heath Fritillary were also seen venturing from nearby sites, but proof that they were using the Woodland Trust site and not just flying past or lost would require finding the butterfly in its earlier stages.

Returning this spring, a team of staff from both Butterfly Conservation and the Woodland Trust searched on hands and knees to look for the caterpillar. Steve's intuition was proven when he was rewarded by spotting the first caterpillar basking on an oak leaf next to a clump of nibbled cow-wheat. Woodland Trust volunteer Alan Stubbs found the second caterpillar minutes later.

Steve explained: "This discovery proves that Heath Fritillary is now resident at Victory Wood and is an example of how working in partnership is having a positive effect on our native species."

Heath Fritillary is on the wing now and can be seen at Victory Wood and other nearby woodlands. Find out more about Victory Wood on the Woodland Trust website.