Official statistics

These statistics have been produced to the high professional standards set out in the Code of Practice for Official Statistics, which sets out eight principles including meeting user needs, impartiality and objectivity, integrity, sound methods and assured quality, frankness and accessibility. More information on the Official Statistics Code of Practice can be found at Code of Practice for Statistics (statisticsauthority.gov.uk).

Click PDF or XLSX or ODS to access the 2023 Summary of Changes table for the UK. The table includes trend estimates for 58 species regularly recorded in the UK and for which sufficient data is available. Indices are calculated for all species using the Generalised Abundance Index (GAI) method developed in 2016 (Dennis et al (2016) BIOMETRICS: DOI: 10.1111/biom.12506) which uses data from all standard BMS all-species butterfly transects, targeted single species surveys and wider countryside butterfly survey squares. The number of sites monitored is a count of all sites on which a species has been monitored in the current analysis year, including those sites on which a species was absent but has been formerly recorded, and thus contribute to the calculation of the national index. For those species for which there is currently insufficient data to perform trend analyses, the number of sites monitored is the total number of sites in that year on which that species was recorded.

This data download is provided under an Open Government Licence (OGL), which allows free and flexible use and reuse of the data with few conditions. You must abide by these licence conditions. More information is available at (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/)

The Open Government Licence requires users to acknowledge the dataset using the attribution statement provided. The attribution statement for this dataset is:

Contains UK Butterfly Monitoring Scheme (UKBMS) data © copyright and database right Butterfly Conservation, the UK Centre for Ecology and Hydrology, British Trust for Ornithology, and the Joint Nature Conservation Committee, 2020

Click PDF or XLSX or ODS to access the 2023 Country-level Summary of Changes tables for England, Scotland, Wales and Northern Ireland. The tables include trend estimates for all species regularly recorded in the respective countries and for which sufficient data is available. Indices are calculated for all species using the Generalised Abundance Index (GAI) method developed in 2016 (Dennis et al (2016) BIOMETRICS: DOI: 10.1111/biom.12506) which uses data from all standard BMS all-species butterfly transects, targeted single species surveys and wider countryside butterfly survey squares. The number of sites monitored is a count of all sites on which a species has been monitored in the current analysis year, including those sites on which a species was absent but has been formerly recorded, and thus contribute to the calculation of the national index. For those species for which there is currently insufficient data to perform trend analyses, the number of sites monitored is the total number of sites in that year on which that species was recorded. Note: Some country-level changes are based on relatively small sample sizes and thus should be interpreted with caution.

The Open Government Licence requires users to acknowledge the dataset using the attribution statement provided. The attribution statement for this dataset is:

Click here  to access the 2023 official statistics: briefing document.
Click here  to access the 2023 official statistics: technical document.
Click here  to find out about drivers of change.

Click here to see official statistics results for previous years