This year’s capricious summer weather has been an unexpected boon for Britain’s butterflies, with the biggest insect count in the world recording an increase on last year’s all-time low.
Red admirals dominated the Big Butterfly Count as citizen scientists recorded an average of 12 butterflies per 15-minute count, up from nine in 2022.
The gatekeeper was the second most numerous species, followed by the large white, small white and holly blue.
Butterfly Conservation also released data showing big declines in seven of the 17 widespread butterfly species recorded over 13 years of the count.
There had been fears that last summer’s drought could have caused mass deaths among many caterpillars as their food plants shrivelled and died, leading to declines in adult butterflies this year, but Dr Zoë Randle, a senior surveys officer at Butterfly Conservation, said: “We now know that the effects of last year’s drought were not as bad for butterflies as we had feared.
“The mixed weather this year has helped as there has been an abundance of green food plants available for caterpillars, and plenty of nectar-rich flowers for adult butterflies. However, while the number of butterflies recorded this summer has been the highest since 2019, the longer-term trends show worrying declines for some of the UK’s most common butterfly species.”
The Big Butterfly Count data over the last 13 years reveals numbers of the once ubiquitous small tortoiseshell have fallen by 30%, with even larger declines for the speckled wood (-38%), ringlet (-41%), common blue (-44%) and green-veined white (-61%).
The red admiral is one species benefiting from global heating and hit top spot in the count for the first time this summer, its numbers soaring by 338% compared with last year. Its numbers have risen by 78% over the 13 years of the count.
Four other species appear to be thriving in an era of big climatic changes, with long-term increases over 13 years for the painted lady (up 113%), the holly blue (+41%), large white (+27%) and small copper (+66%).
Callout
Dr Richard Fox, the head of science at Butterfly Conservation, said: “While the weather certainly has an impact on numbers from year to year, butterflies, moths and many other species can generally cope with variable weather. What they can’t cope with is habitat destruction. Butterflies need a place to live. If they can feed, breed and shelter, they can thrive.”
Butterfly Conservation is calling on people to create a wild space in any outdoor area to help butterflies, moths and other insects. This could be growing nectar-rich plants on a balcony or leaving a patch of long grass in a garden during the summer.
The top 10 butterflies in 2023
1 Red admiral (248,077 recorded in the Big Butterfly Count)
2 Gatekeeper (222,896)
3 Large white (216,666)
4 Small white (202,029)
5 Meadow brown (162,396)
6 Peacock (149,179)
7 Comma (49,173)
8 Small tortoiseshell (45,364)
9 Holly blue (34,655)
10 Common blue (30,009)
