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

A half-century-long rise in warmer, sunnier conditions—partly due to climate change—has enabled certain British butterfly species to thrive, as revealed by one of the world’s leading insect monitoring initiatives. Yet, the broader trend shows a significant decline in many of the UK’s most iconic butterflies. These findings stem from the UK Butterfly Monitoring Scheme (UKBMS), which has amassed over 44 million records from 782,000 volunteer surveys since 1976. This makes it a key example of large-scale citizen science efforts.

Tracking a shifting landscape

Among the 59 native butterfly species tracked, 33 are in steep decline, while 25 have seen improvement. One species remains undetermined due to limited data. The Red admiral, for example, is benefiting from milder winters, with some individuals now overwintering in the UK. Comma butterflies, known for their frayed wing edges, have rebounded since the scheme began. The Orange tip has increased by more than 40%, and the Black hairstreak—a rare UK species—is recovering thanks to targeted conservation work.

A tale of adaptability and vulnerability

Experts highlight a growing disparity between butterflies that thrive in varied environments and those dependent on specific habitats. Species like the Large Blue, once extinct in 1979, have made a comeback through conservation. However, others, such as the white-letter hairstreak, have plummeted by 80% since the surveys started. The pearl-bordered fritillary, with its striking orange-and-black pattern, has also declined by 70%. These losses underscore the fragility of specialist species.

“Most British butterflies reach their northern range limit in the UK, so they have opportunities to expand further north into northern England and Scotland,” says Prof Jane Hill, a butterfly expert at the University of York. She describes the data as “extraordinary” and a global benchmark for wildlife research.

Some butterflies, like the small tortoiseshell, are even bucking expectations. Despite being once widespread, their numbers have dropped by 87%, illustrating how even adaptable species face challenges. Prof Richard Fox of Butterfly Conservation notes that the loss of biodiversity in simplified landscapes mirrors the decline of traditional high street shops and skills.

Conservation in action

The UKBMS relies on an extensive public effort, with volunteers logging over 932,000 miles across more than 7,600 sites. Steve Wilkinson of the Joint Nature Conservation Committee emphasizes the importance of this data: “Without this evidence timeline, we would be flying blind.”

Protecting habitats remains central to conservation, especially as land-use changes threaten ecosystems. Some species, like the Duke of Burgundy, depend entirely on primroses and cowslips, while the purple emperor relies on specific willows. This dietary specificity complicates survival efforts. Butterfly Conservation’s Magdalen Hill Downs reserve, for instance, focuses on maintaining diverse habitats to support these needs.