'Extinction alarm' as UK butterfly species in long-term decline after numbers collapse

More than half of UK butterfly species are now in long-term decline, with figures revealing a dramatic collapse in numbers as Scotland is amongst the worst-hit regions.

Wildlife charity Butterfly Conservation has sounded the alarm following the release of data from its Big Butterfly Count, which showed the average number of butterflies spotted per count had fallen to just seven - a drop of nearly 50 per cent from last year’s average of 12.

It is the lowest figure since the citizen science project began 14 years ago. Experts point to a combination of long-term habitat loss, climate change and pesticide use as the key drivers of the crisis. A wet spring and cooler summer further exacerbated the pressures already facing vulnerable populations.

The chalk hill blue butterfly has suffered its worst recorded decline in terms of numbers | Butterfly Conservation

More than 9,000 counts recorded zero butterflies, which is a record. More than 80 per cent of species saw a year-on-year decline, including the once-familiar small tortoiseshell, the chalk hill blue and small copper suffering their worst year ever.

An identifiable favourite is the Small Tortoiseshell, whose abundance has crashed by 86 per cent since the first UKBMS results in 1976. Picture: Iain H Leach | Iain H Leach/Butterfly Conservation

Dr Richard Fox, head of science at Butterfly Conservation, said: “Nature is sounding the alarm. When butterflies are in trouble, we know the wider environment is too. The latest data is a wake-up call. If we don’t act now, we risk losing some of our most treasured species forever.”

These findings follow an already gloomy picture painted earlier this year by the UK Butterfly Monitoring Scheme (UKBMS), which reported more than half of UK butterfly species are now in long-term decline for the first time on record.

The small copper butterfly is in significant decline, the nationwide count has revealed | Butterfly Conservation

In total, 51 of the UK’s 59 resident species declined in 2024 compared to the previous year. Even widespread countryside butterflies - those found in parks and gardens - have struggled.

Scotland has not been spared. The Scotch Argus, a species native to upland and moorland areas north of the Border, suffered its worst summer in the history of the Big Butterfly Count.

Butterfly Conservation is now urging the UK government to declare a national nature emergency and is calling for an outright ban on neonicotinoid pesticides, which are known to harm pollinators. The charity is writing to UK environment secretary Steve Reed demanding the four nations follow other European countries in outlawing these toxic chemicals completely.

Dr Fox said: “If we don’t finally address the long-term drivers of butterfly decline, we’ll face extinction events we’ve never seen in our lifetime.”

Several species listed on the “red list” amid concerns over their survival, the grizzled skipper and small pearl-bordered fritillary, had their worst year on record, the monitoring showed.

Conservationists said those species required specific habitat to survive, which had been destroyed over the past century.

More than 85,000 people took part in the Big Butterfly Count this year, spending time in gardens, parks, school grounds and the countryside to log sightings.

Butterfly Conservation is urging people to help by letting their grass grow between April and September, planting wildflowers, avoiding pesticides, and creating wildlife-friendly spaces in their gardens. Councils are being encouraged to mow less and protect green spaces.

Dr Fox said: “The solutions are simple, and the impact can be immediate. Butterflies can bounce back, but only if we give them a chance.”

Dr Marc Botham, butterfly ecologist at the UK Centre for Ecology & Hydrology, said: “These deeply concerning results from the UKBMS emphasise just how important it is to monitor and record our wildlife, so we can target conservation efforts and protect our beloved species.”