Newly released data has shown that 2024 was one of the worst years on record for butterflies in the UK. More than half of butterfly species in the UK are now in long-term decline and over a third are showing significant declines.
The data come from the UK Butterfly Monitoring Scheme (UKBMS), which is led by Butterfly Conservation, the UK Centre for Ecology & Hydrology (UKCEH), British Trust for Ornithology and the Joint Nature Conservation Committee. It has asked volunteers to count butterflies across the country since 1976 and now monitors more than 3,000 sites.
The data show that, amid adverse weather conditions, nine species had their worst year since counting began in the 1970s, including a number of common and widespread species found across the UK such as Small and Large Skippers, Small Copper and Green-veined White.
This also included one of the UK’s garden favourites, Small Tortoiseshell, which suffered another incredibly poor year. Found across a wide range of habitats including gardens, this once common and abundant butterfly has shown significant declines in abundance across the UK both in the long-term and over the past 10 years.
Overall, 2024 was the fifth worst year since 1976. In total, 51 of the UK's 58 resident species analysed declined in 2024 compared to 2023, with just six species showing any increase.
Importance of monitoring
Dr Marc Botham, Butterfly Ecologist at UKCEH, said: "These deeply concerning results emphasise just how important it is to monitor and record our wildlife so we can target conservation efforts and protect our beloved species. Butterflies in particular are valuable not just in their own right but also as indicator species, meaning they can tell us about the health of the wider environment, which makes the UKBMS data invaluable in assessing the health of our countryside and natural world in general.
“We are therefore very grateful to the thousands of skilled volunteers who got out to monitor butterflies month after month, year after year, in all weather, which enables us to build up this invaluable dataset.”
Butterfly numbers always fluctuate annually, and last year's low numbers are largely the result of a wet spring and relatively cool summer. However, the UKBMS data also show that 31 of the 59 resident UK species are now in long-term decline. Human activities are preventing populations from recovering including climate change - which is resulting in more extreme weather events - and loss of habitats.
Let garden go wild
Out of the butterflies that had their worst year on record in 2024, Grizzled Skipper, Small Pearl-bordered Fritillary and Chalk Hill Blue are already listed as threatened on the GB butterfly Red List.
However, others were ‘wider countryside’ species such as Small Tortoiseshell, Green-veined White, Small Skipper, Large Skipper and Small Copper. The abundance of Small Tortoiseshell, which lives in all parts of the UK and drinks nectar from a wide variety of flowers, has plummeted 86% since records began.
The organisations behind UKBMS say landowners and members of the public can support butterfly populations by creating suitable habitat for insects. Research shows that letting parts of your garden grow wild with long grass increases the number and variety of species that you see.
The data are available on the UKBMS website.