The latest annual results from the UK Butterfly Monitoring Scheme, recently published (28 March 2025), show that 2024 was one of the worst years on record for butterflies in the UK.
The UK butterfly abundance statistics from the UK Butterfly Monitoring Scheme (UKBMS), led by Butterfly Conservation, the UK Centre for Ecology & Hydrology (UKCEH), British Trust for Ornithology (BTO) and JNCC, present butterfly population trends from 1976 to 2024 at a UK level for 58 of the 59 regularly occurring species.
Overall, the latest findings show that 2024 was one of the worst years on record for butterflies in the UK, ranking 45th in the 49-year series. For the first time since monitoring began more than half of butterfly species (31 out of 59) in the UK are now in long-term decline, with nine species having their worst recorded year, including Small Tortoiseshell, Chalk Hill Blue and Small Copper. In addition, common butterflies, that live in gardens, parks and the wider countryside, had their second-worst year since 1976. In the shorter-term, compared to the previous year (2023), 51 of the UK's 59 species declined in 2024, and six species showed an increase.
Butterflies are one of the best monitored groups of animals in the UK – the UKBMS began in 1976 and is one of the world's longest-running insect monitoring schemes. The scheme now records data on over 3,500 sites per year and the resulting dataset is a crucial resource for understanding long- and short-term changes in butterfly populations. Butterfly numbers fluctuate annually in response to the weather, and the low numbers in 2024 are partly the result of a wet spring and relatively cool summer. Key drivers for longer-term trends include changes in the extent, condition and fragmentation of habitats caused by land-use practices, urban development, pollution and climate change.
The UK Butterfly Monitoring Scheme is one of JNCC’s 11 schemes that monitor species throughout the UK. Monitoring schemes are critical to helping us understand how nature is faring and whether nature conservation and recovery action is effective. These insights, combined with other monitoring data, also enable us to project [forecast] the likely impact of future conservation measures and policies.
Reflecting on the latest results and the value of the scheme, Steve Wilkinson, Director of Ecosystem Evidence & Advice at JNCC, said: "The results revealed by the UK Butterfly Monitoring Scheme highlights why robust wildlife monitoring is absolutely essential for conservation. Without the dedicated efforts of thousands of volunteers tracking butterfly numbers, we wouldn't fully understand the scale of this decline. This comprehensive surveillance allows us to identify which species need urgent intervention, track long-term trends, and measure the effectiveness of our conservation efforts. The UKBMS data doesn't just tell us about butterflies – it provides a critical indicator of the health of our wider environment. In the face of habitat loss and climate change, these monitoring schemes provide the evidence base we need to take meaningful action before it's too late."
UK Butterfly Monitoring Scheme data are collected by thousands of skilled volunteers, without whom this invaluable dataset would not be possible to generate or maintain. The UKBMS partners are incredibly grateful to each and every volunteer for their contribution.