big butterfly count

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Thank you for taking part in big butterfly count 2011!

Big butterfly count 2011 was much bigger than 2010 and was certainly the biggest butterfly count of its kind in the world!

30,000 counts were completed, nearly twice as many as last year and over 34,300 people took part. Many thanks to each and every one of you for making the big butterfly count such a success in 2011.

An amazing total of 322,330 butterflies and moths were counted during the 16th July – 7th August survey period, from the Isles of Scilly to Shetland and Dover to Derry (click here to see maps for 2011).

Bad summer weather hits butterflies

The bad news is that the big butterfly count results show that it was a poor summer for butterflies. The average number of individual butterflies seen per Count was down by 11% compared with 2010 and many species were less abundant than last year. Cold and often unsettled summer weather is thought to be the main cause of the drop this year although, of course, many UK butterflies have suffered long-term declines due to the destruction of their habitats by human activities such as intensive farming. 

One of the biggest losers in 2011 was the Common Blue. It fell from 5th place last year to 12th place in 2011 and its numbers were down 61%. The related Holly Blue and Small Copper also did badly. 

All the common ‘whites’ did badly. Decreases in Large White (29% down) and Small White (21% down), the so-called ‘cabbage whites’, might please some gardeners but the beautiful Brimstone (40% down) and harmless Green-veined White (14% down) also decreased.

The two common migrants included in the big butterfly count had another poor year with Painted Lady numbers down 31% and Silver Y moth numbers down 85%! 

Results 2011

The Gatekeeper was the most common butterfly overall this year, up from 3rd place in 2010. However, its numbers were also down (12%) so the Gatekeeper seems to have clinched the top spot mainly because last year’s most common species (Small White and Large White) decreased by more than it did. The 2011 results for all 21 of the big butterfly count target butterfly and moth species are shown below: 



Grand total





Small White



Large White



Meadow Brown



Red Admiral






Speckled Wood



Green-veined White



Small Tortoiseshell



Six-spot Burnet






Common Blue






Holly Blue



Small Copper



Large Skipper



Marbled White






Painted Lady






Silver Y


The Top 10 species for England, Northern Ireland, Scotland and Wales can be found here.

Butterflies whose caterpillars feed on grasses seemed to have a good year compared to 2010. The Speckled Wood (up 80%), Large Skipper (up 64%), Marbled White (up 34%) and Meadow Brown (up 13%) all increased and the Ringlet was stable. Among common grass-feeding species only the Gatekeeper and Wall decreased. 

Among the colourful, Nymphalid butterflies the picture was mixed. The Red Admiral did really well and was twice as common during big butterfly count 2011 compared with the previous year. On the other hand, the Comma decreased (by 35%), while numbers of the Small Tortoiseshell and Peacock were stable, which was reassuring after their recent severe declines.

The Small Tortoiseshell again showed a distinctive north v south divide in its numbers. The average number of Small Tortoiseshells per count in northern areas (Scotland, Northern Ireland and the far north of England) was 3.7 times greater than the average number in the south (most of England and all of Wales)!

The Six-spot Burnet had a good year (up 34% on 2010) and made it to number 10 – the first time a moth has got into the big butterfly count Top 10. 

The big butterfly count will return again next July to enable us to identify longer term trends in our butterfly species. With your help, we can make it an even bigger and better big butterfly count.

What you said about big butterfly count 2011

We just had to let you know how much some of you have enjoyed participating in the big butterfly count. Below are just some of the inspiring comments some of you have made:

"My 8 and 5 year olds loved doing this!" Mrs S, Greater Manchester

"I really enjoyed carrying out the count and it's great to be able to contribute to this important survey!" Mr S, Cardiff

"I had lots of fun searching for all the butterflies. Mummy, Daddy and me never thought we would find this many" 7 year old, West Sussex

"We have become more interested in identifying them as a result of counting them" Mrs C, Fife

"I realised I had forgotten just how beautiful they are. It was wonderful to be reminded!" Ms W, Leicestershire

We have been inundated with e-mails and suggestions and we would like to thank you all for your comments. Unfortunately we are unable to respond to all your queries and we hope that the e-mail newletters will help to answer some of your questions.

A closer look

Please remember to look at the interactive results page where you can see the results from 2011's big butterfly count.

Why not have some fun using the drop down menus to see the results by individual species or habitat?

Thank you all for your help in making big butterfly count the biggest butterfly event of its kind in the world and enabling us to assess how butterflies and moths have fared. Make sure you and your friends and family take part in big butterfly count 2012 (14th July - 5th August).

See results for your country        See results for different habitats

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