Badger populations in the UK are slowly recovering from low levels due to historic persecution, but they still face various threats, for example badger crime and land use change. The Scottish Badger Distribution Survey 2022-2025 was set up with the aim of producing a current estimate of badger main sett density and distribution in Scotland, with each main sett essentially representing a social group of badgers. Another aim was to assess the change since the previous survey period in 2006-2009. This survey was organised by the charity Scottish Badgers, with BioSS carrying out the design and analysis.

During this survey, trained volunteers assessed hundreds of 1-km squares across Scotland for any badger setts or signs. The 2006-2009 survey, which BioSS also provided statistical support for, was designed based on a stratified random sample of 1000 1-km squares, with stratification by region and habitat type. Not all of these 1000 squares were surveyed in 2006-2009, therefore 892 of these original squares were retained in the design for the 2022-2025 survey to allow direct estimation of change. An additional 108 squares were assigned to ensure a more representative sample of 1000 squares based on current land cover proportions in Scotland. 

Due to volunteer availability and time constraints, a total of 535 squares were surveyed from the original design of 1000. A minimum level of 40% coverage was reached in each region and habitat type through continuous monitoring and targeted volunteer recruitment and training. Coverage was more variable for individual region and habitat combinations, but this was somewhat accounted for in the analysis. This is because estimates were produced by estimating the number of main setts in each stratum separately, then adding across strata. The low levels of coverage and non-random patterns of missing data mean that the results should still be treated with a degree of caution.

Based on the results calculated by BioSS, there are estimated to be between 10290 and 15864 badger main setts in Scotland. Also, an estimated 11% to 14.5% of 1-km squares in Scotland contain at least one badger main sett, with badgers being completely absent from 60-70% of Scotland’s land mass. When comparing results with the baseline survey carried out in 2006-2009, it is estimated that there has been an increase of between 2956 and 6293 1-km squares containing badger main setts over the past 16 years. This is equivalent to an additional 3.7% to 7.9% of 1-km squares in Scotland containing badger main setts since the previous survey. However, it isn’t advisable to estimate the increase in badger population based on main sett estimates.

(c) A Louden

The full survey report and a summary report can be viewed on the Scottish Badgers website at www.scottishbadgers.org.uk.

This work was done in collaboration with Scottish Badgers and NatureScot, and was funded by the National Lottery Heritage Fund.