Britain counts 1.4 million butterflies and moths in second-best season in 16 years
Britain experienced its second-best butterfly season in 16 years during the summer of 2026, driven by record-breaking heat. While migratory species like the painted lady saw massive population surges, experts warn that the drought conditions may lead to a population crash for caterpillars next year.
Why it matters
This event illustrates the complex and often contradictory impacts of climate change on biodiversity, where short-term booms can mask long-term ecological instability.
The record heat of 2026 made this summer exceptional for butterfly-watching. More than 100,000 volunteers fanned across Britain with notebooks this summer, tallying nearly 1.4 million common butterflies and day-flying moths. This was the second-best butterfly season of the past 16 years, according to the Big Butterfly Count. Painted ladies surged by 335% compared with 2025. But this butterfly season could be a warning, according to experts.Britain sees a butterfly boom after a summer of record heatThe record heat of summer 2026 has delivered the second-best butterfly season of the past 16 years in Britain. More than 100,000 volunteers counted almost 1.4 million common butterflies and moths this season. Painted ladies, a migratory species that island-hop from sub-Saharan Africa through several generations each summer, did the heavy lifting. There was a 335% rise in their numbers.
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