The 2025 Big Butterfly Count: A Season of Contrasts for UK Butterflies

The 2025 Big Butterfly Count, a major citizen science project, concluded its survey period from July 18 to August 10, with over 125,000 participants across the United Kingdom recording approximately 1.7 million butterflies and moths. The average count per 15-minute observation period rose to 10.3 butterflies, an improvement from the previous year's record low of seven, though still below historical averages, indicating a complex situation for butterfly populations.

This year's count revealed a mixed performance among species. The Large White and Small White butterflies achieved their highest recorded results in the Big Butterfly Count, with the Large White being the most frequently spotted species (396,510 sightings) and the Small White following closely (318,762 sightings). The Jersey Tiger moth also had a record year, observed more widely and in greater numbers than ever before. Conversely, species such as the Holly Blue, Common Blue, and Meadow Brown experienced some of their poorest counts on record. Dr. Richard Fox, Head of Science at Butterfly Conservation, noted that while the increased numbers offer a welcome improvement from 2024's dismal figures, the 15-year trends show more widespread species have declined significantly than have increased. He emphasized that even with generally favorable weather, one-third of species fared poorly, highlighting the persistent impact of habitat loss, climate change, and pesticide use.

In contrast to the UK's butterfly trends, Botucatu, Brazil, is anticipating a hot and dry September, with forecasts predicting high temperatures and low humidity. This follows an exceptionally dry August, marking it as the driest month in recent years. The region's climate is increasingly influenced by broader environmental shifts, with deforestation contributing to reduced rainfall and intensified dry seasons, raising the risk of forest fires. The Brazilian Cerrado, a biodiversity hotspot, is also experiencing rising temperatures and reduced humidity, impacting its ecosystems and water sources. These contrasting environmental conditions serve as a reminder of the interconnectedness of ecological systems and the varied impacts of climate change globally.