Endangered butterfly has best UK summer in 150 years

One of Europe’s most endangered butterflies has recorded its best summer in the UK in over 150 years.

Once extinct in the UK, the large blue butterfly has made a miraculous recovery with thousands of sightings in southwest England this summer.

The success can be attributed to a long-term conservation project, led by the Royal Entomological Society, which brought caterpillars from Sweden just a few years after the butterfly had been declared extinct in the UK in 1979.

Research ecologist David Simcox, along with Oxford University professor Jeremy Thomas, reintroduced the butterfly in 1983, told the BBC of the success: “Obviously you have hope, but the first ten years were difficult; the national population was under 10,000 eggs.

“This success shows that if we can understand the ecological requirements of very rare and difficult species, we can turn back the trend of decline,” but warned: “Two bad years or poor land management could really go against the species.”

This summer conservationists counted 750,000 large blue butterfly eggs, with an estimated 20,000 reaching maturation making southwest England the largest known colony in Europe.

The project saw conservationists focus on restoring a type of wild meadowland where the large blue likes to live. Other rare insects that benefitted from the restoration project were the rugged oil beetle, rock-rose pot beetle, shrill carder bumblebee, downland villa and spotted beeflies.

The sites are run or owned by six organisations, including the National Trust, Somerset and Gloucestershire Wildlife Trusts, J & F Clark Trust, Natural England, and Oxford University.

Despite the butterflies’ success, they remain at severe risk, primarily from extreme weather and climate change which pose a danger, particularly because large blues rely on flowering plants and ant nests.

Image copyright: Royal Entomological Society