Butterfly experts have expressed concern after numbers of the insects collapsed over the summer, though weather conditions should have seen them flourishing.

Reporting the results of its Big Butterfly Count, a citizen science project to monitor butterfly numbers between 15th July and 7th August, the charity Butterfly Conservation revealed that the majority of butterfly species studied as part of the count recorded declines. Butterfly numbers were at their lowest since the count began six years ago.  

Numbers of formerly common species, including the Gatekeeper, small tortoiseshell and peacock almost halved this year. According to Butterfly Conservation, Peacock numbers have fallen sixfold in the past three years. The citizen science project also reported that 2016’s count was the one with the lowest total number of butterflies. Numbers were lower than the wet summer of 2012, which was a disaster year for butterflies.

Richard Fox, head of recording at the butterfly charity said, “The drop in butterfly numbers this summer has been a shock and is a bit of a mystery. When we have cold, wet summers, as in 2012, we expect butterfly populations to plummet, but that wasn’t the case this year.

“The summer months were warmer than usual, yet most Big Butterfly Count participants saw fewer butterflies. Perhaps the very mild winter had a negative effect, or the cold spring, or perhaps the impacts of intensive farming and pesticides are really hitting these common species now.”

Richard Fox continued, “The importance of Big Butterfly Count is that it takes place every year over a long period; the longer it goes on the more we can learn about the causes that are driving the declines and in some cases, increases of our beautiful butterfly species. We are really grateful to the many thousands of people across the UK who do their bit to help butterflies by taking part in the Big Butterfly Count each summer.”