In just three weeks this summer, more than 140,000 Painted Lady butterflies were counted in Scotland as part of the 10th UK-wide Big Butterfly Count.
Run by Butterfly Conservation and sponsored by B&Q, the wildlife charity can confirm that 2019 has been a ‘Painted Lady Year’ – a natural phenomenon that happens about once in a decade, when unusually high numbers of this migratory butterfly arrive in the UK.
Scotland was at the forefront of this spectacle with at least 141,649 Painted Ladies spotted as part of the survey, making up more than half of all the butterflies counted.
The east coast had a massive influx of the brightly coloured butterflies, particularly along the Firth of Forth, which then dispersed through the Central Belt and participants in Scotland saw far more Painted Ladies than people doing the Count in England.
On average, 14 Painted Ladies were seen per count in Scotland this summer, compared to just three per count in England.
It is too early to tell how 2019 compares to the last ‘Painted Lady Year’ in 2009, but the number recorded in this year’s Big Butterfly Count was almost 160 times greater than in the 2018 survey, equating to an increase per Count of 7541% on the year before.
Several other common species have experienced a bumper summer, helped by the fine weather. In Scotland, counts of Ringlet butterflies were up 78% on last year, the Meadow Brown experienced a 28% increase and there was a 27% rise in counts for the Red Admiral, but it was the Small Tortoiseshell which had its best summer since 2014, with counts up 126% on last year.
Big Butterfly Count 2019 – top 10 species ranking (Scotland) were:
1, Painted Lady, 141,649; 2, Small Tortoiseshell, 14,810; 3, Peacock, 13,993; 4, Small White, 13,362; 5, Red Admiral, 7644; 6, Large White, 6957; 7, Green-veined White, 4467; 8, Meadow Brown, 3138; 9, Ringlet, 3089; 10, Speckled Wood, 1464.
Despite this, scientists remain concerned about the Small Tortoiseshell’s long-term future as this once common and widespread butterfly has declined by 78% across the UK since the 1970s.
Butterfly Conservation’s associate director of recording and research, Richard Fox, said: ‘Last year the Small Tortoiseshell experienced its worst summer in the history of the Big Butterfly Count, so to see its numbers jump up this year is a big relief. B
‘ut what’s really interesting when we look at the results is how this species performed far better in Scotland this year – where it was the second most seen butterfly during the count – but didn’t do nearly as well in England, where it only just made the Top 10.
‘On average, participants in Scotland saw over twice as many Small Tortoiseshells per count than people in England.
‘We’re still trying to establish what is behind the long-term decline of the Small Tortoiseshell and while it’s good news that the butterfly fared better this summer, the poor results in southern England in particular suggest that climate change may be having more of an impact on this species than we have previously realised.’
This year across the UK more than 113,500 people took part in the Big Butterfly Count, the largest survey of its kind in the world, spotting nearly 1.6 million butterflies during the three-week, high-summer recording period.
Richard added: ‘The Painted Lady obviously stole the show this summer, taking the top spot in Scotland and overall, but 2019 has also been the most successful Big Butterfly Count in its 10-year history, with twice as many people taking part in Scotland than ever before and a record-breaking number of counts being submitted.’
The warm weather experienced across the UK this summer should have helped most butterflies, but the common white species all suffered slumps.
In Scotland, the Large White, Small White and Green-veined White saw their numbers drop by 55%, 53% and 56% respectively, compared to the same three-week period last year. It is possible that the drop in sightings for some of these species could be the result of increased predation by parasitic wasps, populations of which may have been boosted by the butterflies’ good fortunes across the UK last summer.
The Big Butterfly Count results can be found at www.bigbutterflycount.org and these will be used by scientists to see how the UK’s common species are faring and where to target future conservation work.