Butterfly numbers are dropping but here are five species you may see more of

Butterfly Populations Show Mixed Trends Amid Climate Shifts

Over the past five decades, milder and sunnier conditions—partly a result of climate change—have allowed certain British butterfly species to thrive. However, the broader trend paints a more concerning picture. Data from the UK Butterfly Monitoring Scheme (UKBMS), one of the world’s most extensive insect tracking initiatives, reveals that 33 of the 59 native species monitored are experiencing significant population declines, while 25 have shown improvement. One species remains inconclusive due to limited data.

Climate-Driven Successes

Among the beneficiaries of warmer weather are the Red admiral, which now overwinters in the UK, and the Comma butterfly, whose numbers have rebounded since the scheme’s inception in 1976. The Orange tip population has increased by over 40%, while the Black hairstreak, once among the country’s rarest butterflies, is showing signs of recovery due to targeted conservation measures. Similarly, the Large Blue, which was declared extinct in 1979, has made a comeback through dedicated habitat restoration.

“The data collected by the scheme over five decades is ‘extraordinary’ and sets a global benchmark for wildlife surveys,” said Prof Jane Hill, a butterfly specialist at the University of York. She added that as cold-blooded insects, butterflies benefit from warmer temperatures, enabling them to expand their range into northern England and Scotland.

The Habitat Divide

Yet, the findings highlight a stark contrast between adaptable species and those reliant on specific environments. Butterflies that survive in diverse settings, such as farmland and gardens, have fared better. In contrast, specialists like the white-letter hairstreak and pearl-bordered fritillary—whose caterpillars depend on precise food sources—face challenges. The white-letter hairstreak’s numbers have plummeted by 80%, while the pearl-bordered fritillary has declined by 70%.

“Just as traditional high street businesses have faded, so too have the rich butterfly communities once found in varied landscapes,” noted Prof Richard Fox, head of science at Butterfly Conservation. “Our simplified environments are leaving many species struggling.”

Conservationists emphasize that habitat loss and agricultural intensification are key threats. Some species, such as the Duke of Burgundy, depend entirely on primroses and cowslips, while the purple emperor relies on goat or grey willow. This dependency makes them vulnerable to environmental changes. To counteract this, initiatives like the Magdalen Hill Downs reserve aim to maintain diverse habitats, ensuring a range of resources for different species.

The scale of the dataset underscores the public’s role in preserving biodiversity. Volunteers have logged over 932,000 miles across 7,600 sites, providing critical long-term insights. “Without this evidence timeline, we’d be flying blind,” stated Steve Wilkinson, director of the Joint Nature Conservation Committee. “The consistency of volunteer efforts allows us to track progress and target conservation efforts effectively.”