Britain has recorded its second-best butterfly season in the 16-year history of the Big Butterfly Count, with more than 101,000 participants recording almost 1.4 million butterflies and day-flying moths across the country. The results were released on September 16, 2026, following an exceptionally hot and dry summer.
The warm weather provided favourable conditions for adult butterflies, which are more active in sunny conditions. Migratory Painted Lady butterflies were particularly notable, with sightings increasing by 335% compared with 2025. Holly Blue and Gatekeeper also recorded their best results in the history of the survey.
However, conservationists warn that the strong numbers of adult butterflies may hide a more serious problem. Prolonged drought caused some plants used by caterpillars for food to wither or die before the caterpillars could complete their development. This could reduce butterfly numbers in 2027.
Drought-sensitive species have already shown declines, including Speckled Wood, Green-veined White and Ringlet. The UK’s Met Office has also reported that summer 2026 was provisionally the hottest summer on record, with very dry conditions across many areas.
Conservation experts say continued monitoring will be important to determine how the extreme weather affects butterfly populations in the coming years.
News as reported
