Butterfly numbers are dropping but here are five species you may see more of
Butterfly numbers are dropping but here are five species you may see more of
Over the past 50 years, the UK Butterfly Monitoring Scheme (UKBMS) has tracked the changing fortunes of Britain’s butterfly populations. This extensive project, supported by over 782,000 volunteer surveys since 1976, has amassed more than 44 million records, making it a cornerstone of global citizen science initiatives. Despite these efforts, the data reveals a concerning trend: many iconic butterfly species are experiencing sharp declines, while others are adapting to shifting environmental conditions.
A mix of gains and losses
The findings underscore a split between species that are thriving and those struggling. Some butterflies, like the Red admiral, have seen their numbers grow as milder winters allow them to overwinter in the UK. Comma butterflies, noted for their frayed wing patterns, have rebounded since the survey began. Similarly, Orange tips have increased by over 40%, and the Black hairstreak, once rare, is now showing signs of recovery due to targeted conservation work. The Large Blue, which vanished in 1979, has also improved thanks to habitat restoration.
However, the picture is far less optimistic for others. The white-letter hairstreak has plummeted by 80%, while the pearl-bordered fritillary has dropped by 70%. These declines are linked to habitat degradation and the shrinking availability of specific plants that caterpillars rely on for survival. For instance, the Duke of Burgundy depends solely on primroses and cowslips, and the purple emperor requires goat or grey willow.
“Butterflies are cold-blooded, so warmer conditions often benefit them,” says Prof Jane Hill of the University of York. “Many British species reach their northern limits in the UK, giving them a chance to expand further north into Scotland and northern England.” She highlights the UKBMS data as a “gold standard” for wildlife monitoring, emphasizing its long-term reliability.
Adaptable vs. specialists
The study points to a growing disparity between generalist and specialist butterflies. Species that can survive in diverse environments—such as farmlands or urban gardens—are generally faring better. In contrast, those dependent on specific habitats, like woodland clearings or chalk grasslands, are under threat. Their inability to adapt to habitat loss or climate shifts has led to rapid population drops.
“Just as traditional high street businesses have disappeared, so too have the rich butterfly communities that once thrived in varied landscapes,” notes Prof Richard Fox, head of science at Butterfly Conservation. “Our fragmented environments are reducing the diversity of species we see.”
Conservationists stress that protecting habitats remains critical. Projects like the Magdalen Hill Downs reserve aim to preserve a mosaic of environments to support both common and rare butterflies. Yet, challenges persist, as some species demand highly specialized conditions. “Without this evidence timeline, we’d be flying blind,” says Steve Wilkinson of the Joint Nature Conservation Committee. “The volunteers’ data is essential for guiding conservation strategies effectively.”
The UKBMS reflects a massive public contribution, with volunteers logging over 932,000 miles across 7,600 sites. This effort highlights the importance of sustained observation in understanding ecological shifts and directing conservation priorities. While some butterflies are gaining ground, the overall trend signals a need for continued action to safeguard the UK’s diverse insect life.
