A warm and sunny spell in the summer of 2022 led to increased sightings of certain butterfly species such as the Gatekeeper and Common Blue but overall numbers are still “worryingly low”, experts have said.
Sightings of the Comma, a popular species often found in gardens, increased by 95% compared with last year, according to the results from the annual Big Butterfly Count in the UK.
The Gatekeeper, a species often found along hedgerows and woodland rides, as well as in gardens, was the most spotted butterfly during this year’s count, reporting a 58% increase from last year.
But experts are worried the UK’s population of butterflies and day-flying moths is still in decline. Wildlife charity Butterfly Conservation described the numbers as “worryingly low”.
Dr Richard Fox, head of science for Butterfly Conservation, said: “We might have expected this summer to have been a much better one for butterflies given the good weather we experienced in many parts of the UK.
“The fact that more butterflies weren’t seen is concerning and it’s clear that much more needs to be done to protect and restore habitats to aid nature recovery.
“The sun could shine for days on end, but we still won’t see more butterflies unless there is habitat for them to thrive in.”
Almost 100,000 butterfly counts were carried out Between July 15 and August 7, with citizen scientists spending a combined total of over two-and-a-half years counting different species in their gardens, local parks and in the countryside.
The results show an average of just under nine butterflies seen per count, which the conservationists say, is an all-time low in the 13 years since the project began.
Among the species that bounced back are the Common Blue and the Holly Blue, with increases of 154% for the Common Blue and 120% for the Holly Blue.
The Holly Blue butterfly had only occasionally been recorded in Scotland prior to the 2000s, but after becoming firmly established in Edinburgh from 2006 and in Ayr from 2008, the species has subsequently spread across swathes of Scotland, the experts said.
The Comma has also been making a slow comeback from its low point in the 1910s and expanding its range rapidly northwards, the team added.
Dr Zoe Randle, senior surveys officer at Butterfly Conservation, said: “The vast majority of Big Butterfly Counts are done in gardens, which makes this data especially valuable because this type of habitat is under-represented in many of our other schemes.
“We can create habitat for butterflies such as the Holly Blue and Comma in our gardens, by cultivating Holly and flowering Ivy for the former and growing Hop, elms and nettles for the latter.
“Gardens that are wildlife friendly can provide vital habitat for these insects, allowing them space to feed, breed and shelter.”
The Big Butterfly Count is one of largest citizen-science project of its kind, helping scientists gather important data on how butterflies and moths are coping with changing climate and habitat loss.
Next year’s Big Butterfly Count will take place from July 14–August 6 2023.