It may not have been a bumper summer for butterflies, but the UK public defied the cold, wet weather to make big butterfly count 2015 the biggest ever.

Impressive new records for big butterfly count participation were set. Over 52,000 people took part in the 2015 event, smashing the previous high of 46,400 in 2013. For the first time over 50,000 counts were submitted via the website and free smartphone apps, from St James’s Park in central London to Sutherland. We also had the highest ever big butterfly count effort on a single day during this year’s event – over 5,300 counts were completed on Saturday 8 August. A huge thank you to everyone who took part this year!

In the six annual big butterfly count events that have taken place so far, over 208,000 counts have been undertaken, each a 15 minute survey for 20 target species of butterflies and moths.

As usual, Sir David Attenborough led the publicity for this year’s big butterfly count with interviews on television and radio, as well as widespread coverage in the newspapers and online. As a result, almost 108,000 people visited the big butterfly count website between April and August.

Ups and downs
During the official big butterfly count 2015 period (17 July – 9 August) almost 585,000 individual butterflies and moths of the 20 target species were counted and logged online. The average number of individual butterflies seen per count decreased from 15 last year to 13 this year (a 9% decrease), no doubt due to the weather. Declines in the overall abundance of butterflies seen were even more stark in Northern Ireland (41% down) and Scotland (37% down), which suffered disproportionately bad weather, particularly during July.

Despite this overall decrease, more of the big butterfly count target species showed increases compared with last year than vice versa. Eleven species increased over 2014, seven decreased and two remained at more or less the same levels.

The biggest increase was achieved by the Holly Blue (151% increase on 2014), which recovered from a run of three poor summers to record its joint highest big butterfly count total. Gatekeeper numbers only increased modestly (up 17% on last year), but reached their highest levels in the six years of big butterfly count. The Painted Lady also had a good year (numbers up 28% on 2014) and notched up its second best big butterfly count performance.

The Large White improved on its poor showing last summer (with numbers up by 46%), but its close relatives the Small White and Green-veined White didn’t follow the same trend. Numbers of Small White remained at similar levels to last year, while Green-veined White populations decreased.

Disappointingly, several species that did well in big butterfly count 2014 fell back this summer. Last year’s winner, the Peacock decreased substantially from the high numbers seen in the summers of 2013 and 2014. Its counts were down 61% on 2014, but still remain much higher than in the awful summer of 2012. Its close relative, the Small Tortoiseshell, also suffered a reversal of its recent resurgence, but thankfully did not fall to the very low levels that were causing such concern among butterfly enthusiasts a few years ago. Small Tortoiseshell numbers fell by 57% compared with 2014, but were still more than double those recorded in 2012.

Red Admiral and Speckled Wood also decreased this summer, declining by 28% and 25% respectively compared with big butterfly count 2014.

Species results 2015
The Gatekeeper secured its second big butterfly count win (having also taken top spot in 2011) with its highest abundance since the project started in 2010. Large White numbers improved considerably and the species reached second place after its lowest position last year (6th). Ringlet achieved its second highest position since big butterfly count started, while the 9th place for the Comma was its best result yet.

Green-veined White, on the other hand recorded its lowest big butterfly count position, the first time it has been outside the top 10.

The big butterfly count will return again next summer (15 July – 7 August) to enable us to identify longer term trends in our butterfly species. With your help, we can make it even bigger and better in 2016. www.bigbutterflycount.org