Wider Countryside Butterfly Survey
The Wider Countryside Butterfly Survey (WCBS) is BTO’s main scheme for monitoring population changes of the UK’s common and widespread butterflies.
About the Wider Countryside Butterfly Survey (WCBS)
The Wider Countryside Butterfly Survey feeds into the UK Butterfly Monitoring Scheme (UKBMS), a long-term monitoring scheme running since 1976 - it celebrates its fiftieth birthday in 2025! - that is important in both assessing the changing status of widespread butterfly species and in providing an indicator of the health of the wider countryside.
The UKBMS involves repeat survey sampling at thousands of locations across the UK. The key method involves weekly counts of butterflies along defined transects on days with suitable weather criteria from April to September. The UKBMS also includes butterfly counts from randomly selected Wider Countryside Butterfly Survey squares (which include BTO/JNCC/RSPB Breeding Bird Survey squares) and targeted species surveys.
For more information, visit the UKBMS website, @UKBMSLive on Twitter and @ukbms.bsky.social on Bluesky.
- All BBS volunteers can take part in the WCBS by making extra visits to their square between May and August to count butterflies.
The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation, the Centre for Ecology and Hydrology, British Trust for Ornithology, and the Joint Nature Conservation Committee.
The UKBMS is indebted to all volunteers who contribute data to the scheme and we now have data from the WCBS, carried out on BBS squares spanning back to the pilot years of 2007 and 2008.
Get involved
Squares, instructions and recording forms
download the instructions
recording form
Square allocation for the WCBS on BBS squares and all WCBS data from BBS squares are entered into the UKBMS data entry system. For guidance on how to register your BBS square for the WCBS on the UKBMS website, please email bbs@bto.org.
Entering data for the WCBS
1. Register at www.ukbms.org/mydata/ (register button is at top right hand side of the screen). When choosing your username on this website, it is helpful to us if you use your BTO username.
2. Wait for us to email you to confirm that your account has been linked to your square(s). This can only be done during working hours, so please be patient.
3. Once allocated the square, log in to the UKBMS website. Hover over ‘My Data’ along the top of the page, then hover over 'Walks' and then when it appears, click on 'My Walks'.
4. In the page that opens, it is crucial you change the 'Site Type' to WCBS-BBS in the drop down menu, 'Filter by site' by selecting the square you are entering data for and then find the date of your WCBS survey in the calendar and click on the little green ‘plus’ sign. You can now enter and save the datas from your visit.
Latest results
The UK Butterfly Monitoring Scheme (UKBMS) 2024 Official Statistic has been released. This includes data collected by the c.300 BBS volunteers who take part in the Wider Countryside Butterfly Survey on their squares each year.
- The Official Statistic describes the trends of 58 out of 59 of the regularly occurring butterfly species in the UK.
- It is based on the results of the UKBMS, including data from BTO volunteers who contribute to the WCBS.
Butterfly populations fluctuate naturally from year to year. However, records in the UKBMS dataset begin as early as 1976, which allows us to identify long-term population trends. Unfortunately, the results show that 2024 was officially one of the worst years on record for UK butterflies.
The UKBMS figures come after Butterfly Conservation declared a UK-wide Butterfly Emergency following the worst-ever results of its Big Butterfly Count last year.
2025 report headlines
- More than half of UK butterfly species are now in long-term decline
- Small Tortoiseshell had its worst year ever and is in long-term decline
- Common butterflies that live in gardens, parks and the wider countryside had their second-worst year since 1976
- 51 of the UK's 59 species declined in 2024 compared to 2023
In more detail
Nine species had their worst year since counting began, including the much-loved Small Tortoiseshell, Chalk Hill Blue and Small Copper.
Overall, 2024 was the fifth-worst year since records began for UK butterflies. Butterfly numbers always fluctuate annually, and last year's low numbers are partly the result of a wet spring and relatively cool summer. However, UKBMS data also show that 31 of the 59 resident UK species are now in long-term decline.
In total, 51 of the UK's 59 species declined in 2024 compared to 2023, with just six species showing any increase.
Spotlight on the Small Tortoiseshell
Among the most concerning species is the Small Tortoiseshell: one of the most well-known butterflies in the UK, its bright colours and appearance in gardens have made it a recognisable favourite.
However, since the first UKBMS results in 1976, its abundance has plummeted by 86%. Numbers in 2023 were the worst ever at that point, and last year were down again. It is now in significant long-term decline in all four UK countries.
Unlike many of the species that are faring worst, the Small Tortoiseshell is not a rarity confined to nature reserves but a 'wider countryside species', living in all parts of the UK and drinking nectar from a wide variety of flowers. Its caterpillars feed on stinging nettles.
Other species of concern
The Green-veined White, the UK's most widespread butterfly, is also now in significant long-term decline.
The Grizzled Skipper, Small Pearl-bordered Fritillary and Chalk Hill Blue, which also had their worst year on record, are already listed as threatened on the GB butterfly Red List.
A few signs of hope
Despite the significant declines mentioned above, the following familiar species have increased in recent times across the UK:
- Red Admiral
- Peacock
- Meadow Brown
Other species that have increased include Lulworth Skipper, Heath Fritillay and White-letter Hairstreak.
- Read more about the latest results on the UKBMS website >
Publications
The latest publications using WCBS data can be viewed on the BBS-related reports and newsletters webpage. This includes the WCBS newsletters and the UKBMS Annual Report.
The UKBMS Official Statistics can be viewed on the UKBMS website.
WCBS Partners
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