Another disastrous summer for butterflies

Common butterflies saw their numbers collapse over the summer despite the UK experiencing weather conditions that usually help them thrive, results from the Big Butterfly Count have revealed.

The majority of butterfly species studied as part of the scheme saw their populations fall, with some producing their worst numbers since the Big Butterfly Count scheme began. Widespread species such as Gatekeeper, Comma and Small Copper experienced their worst summers in the project's history and were down 40%, 46% and 30% respectively compared to last year. Small Tortoiseshell saw a 47% drop in numbers and Peacock slumped by 42%, both species recording their second-worst years.

Numbers of the colourful Peacock have now dropped from an average of 3.6 individuals per count in 2013 to just 0.5 per count in 2016, a sixfold decrease over three years. Participants also saw the lowest number of butterflies per count since the scheme began: an average of just 12 butterflies spotted. These figures were even lower than those experienced during the cold and wet disaster summer of 2012 — the worst year on record for UK butterflies.

An awful summer for Peacock saw their numbers slump by 42 per cent (Photo: Mr E Williams)

These falls come despite the summer of 2016 being warmer than average and relatively dry — conditions butterflies typically depend upon in order to breed and feed successfully . Reasons why butterflies have struggled despite favourable summer weather conditions are as yet unclear.

Butterfly Conservation's Head of Recording, Richard Fox, 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.

"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."

Red Admiral and Green-veined White bucked the negative trend to experience good years. The former was up 70% compared to 2015, had the largest year-on-year increase of any species and achieved its second-highest abundance since the Count began. Green-veined White was up by 58% compared to last year and was the only one of the common white butterfly species to experience a substantial rise in numbers.

Green-veined White was up 70 per cent compared to 2015 (Photo: Bob Eade)

The most commonly seen species was Large White, up 2% from last year and topping the Count for the first time. Large White's position can be attributed to other species experiencing poor years rather than the butterfly faring particularly well.

Over 36,000 people took part in this year's Count, spotting around 390,000 butterflies during the three-week mid-summer recording period. The Big Butterfly Count helps Butterfly Conservation find out how the UK's common species are faring and how to best protect them in the future. Results can be found at www.bigbutterflycount.org.

2016 Big Butterfly Count Top 10