Butterfly numbers have recovered after a poor summer in 2024, but despite the record-breaking hot summer of 2025, the annual Big Butterfly Count only saw average numbers of these insects. More than 125,000 volunteers participated in the world’s largest insect survey this summer, documenting an average of 10.3 butterflies per 15-minute count across Britain’s parks, gardens, and green spaces.
This marked a significant improvement over the previous year, when a record low of just seven butterflies per count were recorded. The large white butterfly saw a 131% increase in sightings compared to the previous year, with similar increases for the small white (up 128%) and red admiral (up 185%).
However, Butterfly Conservation warns that the numbers have only returned to average levels, with more butterflies counted per count in 2023 and every summer from 2016 to 2020. Dr. Richard Fox, head of science at Butterfly Conservation, notes that while many species saw a better than average summer, a third of species fared poorly even in favorable weather conditions.
The large and small whites recorded their best-ever Big Butterfly Count results, while the day-flying Jersey tiger moth was seen more widely and in higher numbers than before. Unfortunately, the holly blue had its second-worst result and the usually abundant meadow brown its fourth-worst, possibly due to its unusual early flight period, finishing before the count began on July 18th.
The small tortoiseshell, which had its worst-ever result in 2024, made a comeback but has still seen a 60% decline since 2011. Over the past 15 years, some species have shown significant increases, including the large white, red admiral, and small copper.
Dr. Fox stressed the urgent need for action to support butterfly populations, including improving their habitats, reducing pesticide use, and addressing environmental challenges. Until these issues are addressed, it is unlikely to see a significant recovery in butterfly numbers, regardless of the weather.
Source: https://www.theguardian.com/environment/2025/sep/09/britains-butterflies-bounce-back-in-annual-count-but-only-to-average-levels
