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
The UK Butterfly Monitoring Scheme (UKBMS) has revealed a concerning trend in butterfly populations over the past 50 years. While some species have benefited from milder winters and longer growing seasons linked to climate change, the overall decline of many iconic butterflies underscores a broader ecological challenge. This long-running citizen science project, which began in 1976, has compiled over 44 million records from 782,000 volunteer surveys, offering one of the most comprehensive datasets on insect populations in the UK.
Species on the rise
Despite the overall decline, certain butterflies have shown improvement. The Red admiral, for instance, has become more common in the UK as warming temperatures allow it to overwinter locally. Comma butterflies, noted for their frayed wing edges, have seen population growth since the survey began. Orange tips have increased by more than 40%, while the Black hairstreak, once rare, is recovering due to targeted conservation initiatives. The Large Blue, which vanished from the UK in 1979, has also rebounded thanks to habitat restoration efforts.
A growing divide in survival
Prof Jane Hill of the University of York calls the UKBMS data “extraordinary,” emphasizing its role as a benchmark for global wildlife studies. She notes that butterflies, being cold-blooded, thrive in warmer conditions, which has enabled species at their northern range limits to expand into Scotland and northern England. However, specialists reliant on narrow habitats—such as woodland clearings or chalk grasslands—are struggling. These species face steep declines as their environments shrink due to land-use changes and environmental degradation.
Volunteers have contributed over 932,000 miles of data collection across 7,600 sites, according to Steve Wilkinson of the Joint Nature Conservation Committee. “Without this evidence timeline, we would be flying blind,” he said. The scheme’s success hinges on the consistency of its volunteer-driven data, which helps pinpoint where conservation efforts are effective and where more action is needed.
Some butterfly species exhibit extreme dietary specialization. For example, the Duke of Burgundy caterpillars depend solely on primroses and cowslips, while the purple emperor’s larvae feed exclusively on goat or grey willow. This pickiness makes them vulnerable when their food sources dwindle. Butterfly Conservation’s Magdalen Hill Downs reserve reflects this by maintaining diverse habitats to support such species.
Prof Richard Fox, head of science at Butterfly Conservation, highlighted the loss of biodiversity in UK landscapes. “We’ve lost variety and diversity in butterfly communities, much like traditional skills from our high streets,” he remarked. The findings suggest that as natural environments become simpler and fragmented, certain species are disappearing while others adapt and thrive.
