Badgers busy building more setts

Things are looking better for the badger as the number of setts across England rises.
Things are looking better for the badger as the number of setts across England rises. A new survey has found that the total number of badger setts across England and Wales has increased over the last 25 years, but what does this mean for actual badger numbers? 

The European badger (Meles meles) has enjoyed full protection in the United Kingdom since 1992. However, this iconic creature is currently at the centre of a heated public debate over the spread of bovine tuberculosis. This disease (Mycobacterium bovis) causes enormous distress to cattle and dairy farmers whose animals are immediately slaughtered if they are found to be infected. Because badgers can also harbour bTB, many now advocate the culling of badgers as a means of controlling the disease.

However, the link between badgers and the spread of bTB is far from clear, partly because of a lack of information on the population size of badgers in the UK. Badgers themselves are not easy to count – they are elusive, nocturnal creatures and spend much of their time underground. But badger setts (networks of tunnels carved out by badgers) are far easier to assess. So researchers recently completed a survey of badger setts in England and Wales, and were then able to provide an estimate of the total number of badger social groups across rural areas.

The survey, carried out between 2011 and 2013 by trained professionals, showed that active main badger setts were present in just over a third of all areas surveyed. This equated to a sizable total of 71,600 social groups across England and Wales.

To put these figures in context, the authors compared the results with similar surveys carried out in the 1980s and 1990s. They found that over the last 25 years, the number of active badger setts had doubled in England, but that there was little change in Wales. Differences in habitat may largely account for this – badgers are better suited to the open mixed agricultural land of southern England rather than the more marginal Welsh uplands. This steady increase in badger social groups also suggests that the quality of habitat for wildlife has improved over the years, particularly for ground invertebrates and earthworms, which are the badgers’ main food source. Greater protection and awareness of badger conservation may have also contributed to the rise in sett numbers.

Yet it should be pointed out that these results do not necessarily mean that there has been a massive boost in the actual badger population. The numbers of individuals belonging to each social group can vary enormously; consequently, badger sett surveys are simply unable to provide an accurate estimate of total badger abundance. Fortunately, the authors hope to provide some sort of answer by completing a project which aims to estimate the average sett group size. Undoubtedly, such a result will be of great interest to the public and government agencies alike.

Reference: Judge J, Wilson GJ, Macarthur R, Delahay RJ, & McDonald RA (2014). Density and abundance of badger social groups in England and Wales in 2011-2013. Scientific reports, 4 PMID: 24457532

Image: NPWS


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