The unpredictable summer weather this year has unexpectedly benefited in increasing UK butterfly count , with the largest insect count globally recording an increase compared to last year’s all-time low.
The Big UK butterfly Count was dominated by Red Admirals, as citizen scientists documented an average of 12 butterflies per 15-minute count, up from nine in 2022. The second most numerous species was the Gatekeeper, followed by the Large White, Small White, and Holly Blue.
However, Butterfly Conservation also released data indicating significant declines in seven of the 17 widespread butterfly species documented over the past 13 years of the count.
Concerns had arisen that last summer’s drought might have led to mass caterpillar deaths due to the withering of their food plants, resulting in reduced adult butterfly populations this year. However, Dr. Zoë Randle, a senior surveys officer at Butterfly Conservation, stated, “We now know that the effects of last year’s drought were not as severe for butterflies as we had feared.”
Weather
The varied weather this year has been beneficial because it provided an abundance of green food plants for caterpillars and nectar-rich flowers for adult butterflies. Nonetheless, despite this summer’s record numbers, longer-term trends indicate troubling declines for some of the UK’s most common butterfly species.
Data from the Big Butterfly Count over the past 13 years reveals a 30% decline in Small Tortoiseshell numbers, with even more substantial declines for species like the Speckled Wood (-38%), Ringlet (-41%), Common Blue (-44%), and Green-Veined White (-61%).
The Red Admiral, benefiting from global heating, claimed the top spot in the count for the first time this summer, with numbers soaring by 338% compared to last year and a 78% increase over the 13-year count.
Four other species also seem to be thriving amidst significant climatic changes, with long-term increases over 13 years for the Painted Lady (up 113%), Holly Blue (+41%), Large White (+27%), and Small Copper (+66%).
Dr. Richard Fox, the head of science at Butterfly Conservation, emphasized that while weather has an impact on numbers from year to year, habitat destruction is the primary threat. He stressed that butterflies need suitable habitats for feeding, breeding, and shelter to thrive.
Butterfly Conservation is encouraging people to create wild spaces in outdoor areas to support butterflies, moths, and other insects. This can involve growing nectar-rich plants on a balcony or leaving a patch of long grass in a garden during the summer.
