Once-in-a-decade 'painted lady summer' sees huge numbers of migratory butterflies arrive in the UK

Published: 00:11, 24 July 2026 | Updated: 00:15, 24 July 2026 The UK is enjoying a once-in-a-decade 'painted lady summer' when huge numbers of the migratory butterflies arrive and breed here, conservationists have said. Wildlife charity Butterfly Conservation is urging members of the public to count the painted ladies they see as part of its annual Big Butterfly Count, which helps experts assess how butterflies are faring each year. The charity says warm weather across Europe this spring prompted millions of painted ladies to flock to the UK, with clouds of butterflies seen feeding and mating in some spots, and their offspring are now emerging around the country. A 'painted lady summer' only occurs around every 10 years and sees soaring numbers of the butterflies with distinctive orange, black, and white patterned wings. The migration the painted ladies undertake from sub-Saharan Africa to Europe is one of the world's longest insect journeys, and takes successive generations to complete – so that the painted ladies which leave Africa are not those that arrive in the UK to breed, experts said. Adults born in sub-Saharan Africa during the winter fly to north Africa where they mate and lay eggs, with those offspring then migrating across the Mediterranean Sea to southern Europe and mating and laying eggs. The generation which was born in southern Europe in turn arrived in the UK in late spring, mated and laid eggs, and now a new generation of 'home grown' painted lady adults is emerging across the country. Butterfly Conservation said this year is on track to be the third best year for painted lady numbers on record, after 1996 and 2009, but that will depend on the numbers over the coming weeks. A painted lady butterfly, which are expected to flock to the UK in their millions this year Last year in the Big Butterfly Count, people around the UK reported a total of 15,856 painted ladies – but the last time there was a painted lady summer, in 2019, the total was more than 420,000. Butterfly Conservation said this year's numbers are already significantly higher than last year, and higher than the same point in 2019, suggesting this year's painted lady summer could dwarf the last one. Butterfly Conservation head of science Professor Richard Fox said: 'The inter-continental migration of painted lady butterflies is a wonder of the natural world and one of the longest insect journeys on the planet. 'The numbers we're seeing here at the moment have already dwarfed the total number of painted ladies we saw last year, and we're absolutely delighted. 'With their beautiful pinky-orange, black and white patterned wings, they are one of our most popular species. 'The new generation of painted ladies is emerging across the UK right now prior to flying the next leg of the species' epic journey, and helping to count them is a great excuse to take part in this year's Big Butterfly Count.' Painted lady butterflies feed on many flowers including buddleia – known as the butterfly bush – and their caterpillars feed mainly on thistles, with boom years of the insect helping to manage domineering creeping thistle plants. Why the UK experiences these painted lady summers is not entirely understood, according to Butterfly Conservation, but they are linked to the species' breeding success in Africa and southern Europe earlier in the year. Many butterfly populations have boom and bust cycles because of food availability and predator numbers, while this year's heatwaves have provided perfect conditions for the insects' migration, the charity said. Kate Merry, head of engagement at Butterfly Conservation, said it was a 'very exciting and unexpected twist' to this year's Big Butterfly Count. She said: 'It's astonishing that such a seemingly delicate insect can accomplish this incredible long-distance journey. 'We've already seen absolutely loads of them across the UK, so we are very excited to see how many people report them and where.' To take part in the Big Butterfly Count, which runs until Sunday August 9, people just need to spend 15 minutes in any sunny outdoor spot, such as their garden, park or local countryside, and report their sightings. For more information and to take part people can download the free Big Butterfly Count, or visit bigbutterflycount.org.