European badger habitat
Throughout most of Europe, including here in Britain, the badger is primarily a species of “unimproved” grasslands (i.e., that without intensive livestock grazing, ploughing, reseeding, or application of herbicides and artificial fertiliser) and broadleaf/deciduous or mixed woodland. Typically, setts will be constructed on the periphery of these habitats (i.e., with about 30 m / 100 ft. of the edge) to allow easy access to favoured foraging grounds, and this is particularly the case for setts in woodland adjacent to pasture and cereal or fruit crops. Here we look at the main habitat types chosen by badgers for establishing a sett, but for more information about sett construction and use, please see the main badger setts section.
Sett-ing up home
Badgers live in an underground burrow system, usually dug into a slope, known as a sett, and while proximity to a plentiful and varied seasonal food supply is probably the main factor determining badger presence in an area, we often see clear preferences within a habitat for the location of these setts. There are many descriptions of badger setts in the early literature, and it's apparent from these that woodland and hedgerows were recognised as the preferred sites for their construction. It wasn't until 1963, however, nine years after its inception, that The Mammal Society organised the first National Badger Survey, which aimed to, among other things, identify the broad habitat preferences of the species. An initial review of the data by Ernest Neal, based on just over 4,300 setts from across England, Wales and Scotland, was published in the Society's journal, Mammal Review, in 1972. There was a clear preference for deciduous woodland (49% for Britain as a whole but varying by county, such that 75% of setts in Sussex were in broadleaf woodland) and hedgerows (13%) on sandy soil. Despite the great acreage of coniferous woods in Britain, they were the site of only 7% of setts, and most appear to have been dug before the original deciduous woodland was cleared and replaced.
Between November 1985 and January 1988, a facsimile of The Mammal Society's survey was run when 2,455 one-kilometre squares across Britain were assessed for signs of badger activity, the primary aim being to establish a baseline against which future populations changes could be charted. The results were published in The history, distribution, status and habitat requirements of the badger in Britain during 1990 and catalogued just shy of 2,080 setts, 505 of which were classed as main setts. These setts were mapped according to land class and, again, most main setts were dug in hedgerows and treelines (34%) or deciduous woodland (13%), although somewhat more (22%) setts were associated with coniferous woods/plantations this time around.
Fast-forward to November 1991, when county mammal recorders again assessed setts in their jurisdictions up until May 1993. In their report on the changes in the badger population since 1988, published by the People's Trust for Endangered Species during 1997, Bristol University researchers Gavin Wilson, Stephen Harris, and Graeme McLaren plotted the habitat types in which 576 main setts were found. Once more, a familiar trend was observed, with about one-third of setts found in broadleaved woodland and a further 11% in mixed woodland (i.e., that with deciduous and coniferous trees), meaning deciduous and mixed woods accounted for nearly half of all sett locations. Together, scrub, hedgerows, and grassland accounted for around 30% of sett sites, most of those being in hedgerows, while only around 6% of setts were found in conifer woodland. In the Republic of Ireland, Chris Smal of the Office of Public Works in County Wicklow, found a similar picture from the 565 setts surveyed, 75% of which were in hedgerows, scrub, broadleaf woodlands or treelines and 8% among conifers.
Setts may occasionally also be found in less obvious environments, such as on open moorland, heathland, railway embankments, in coal tips, under buildings or roads, on coastal sand dunes, and even among Iron Age forts. Indeed, upland/moorland, cliffs, and built land each held about 2% of setts covered by the 90s survey, while parkland yielded about 1%, and some 3% were found in quarries or mines. In The Badger in Charnwood Forest, published in 1963, Anthony Squires noted that, while well over half the setts identified during the survey were in or on the edge of woodland, some were also found in more unexpected locations, such as a golf course and the bank of a reservoir overflow. Likewise, Adrian Middleton and Richard Paget, in their 1974 monograph Badgers of Yorkshire and Humberside mentioned that badgers were scarce along the southern bank of the River Ouse and the only setts were those in the banks of the warping drains (artificial drains intersecting farmland to control drainage during high tides) and on a railway embankment. They also described a sett near Sheffield that had been excavated in an old rubbish tip, the inhabitants seen amongst old bottles, bones, and cans, and page 70 of the book contains a lovely shot of a badger digging amongst the rubbish.
It should be remembered that while national assessments of habitat types important to a given animal are vital for conservation planning, the trends identified can sometimes mask local pressures or the versatility of the species. In his 1972 paper, for example, Neal noted that, for Scotland as a whole, only about 2.5% of setts were found in moorland, but this was significantly higher in some counties, such as Roxburghshire, in the Scottish Uplands, where moorland is the prevailing landscape and the site of 27% of setts. Similarly, only about 4% of badger setts found during the 91-93 survey were on arable land, but it's unclear whether this reflects agricultural land being less attractive to badgers, or an intolerance of farmers and landowners to their presence. Indeed, many of the badger groups surveyed during the analysis reported increased persecution of, and/or hostility towards, badgers following a campaign by The National Farmers' Union during the early 1990s promoting widespread badger culling as the only solution rising tuberculosis infections among cattle. Certainly, we know that agricultural land will usually be included within a clan's territory, and badgers are drawn to farmland to forage, particularly in maize crops and cattle pastures, the short grass of the latter providing ideal conditions for worming. So, while badgers certainly seem to prefer broadleaf woodland and hedgerows, they are adaptable, and it seems that it's only very high-altitude sites (i.e., above about 400 metres /1,300 ft. in elevation, where food is scarce) and flooded ground (e.g., marsh/fen/bog) that is actively avoided as a site for setts in Britain.
Outside of Britain, in his Mammals of Eastern Europe and Northern Asia, published in 1962, Sergej Ognev described badgers having been found living in desert and semi-desert regions, “making their burrows in sand dunes and old mounds in the Kalmuck and Kirgiz steppes and in Turkestan”. Ognev cites Russian naturalists who have encountered them in the sparse steppe ravines of the Mugan Steppe and among bare rocks in the Bureya mountain range.
Metropolitan meles?
The point at which badgers first became associated with human conurbations is lost in the annals of time, but while the species has likely taken advantage of human cultivation and waste for millennia, setting up home in and around towns and cities appears to be a relatively recent phenomenon. Equally difficult to know is whether badgers actually choose municipal living or we built around them and they simply don't move, although several naturalists have suggested it's more likely the latter.
In 1959, the mammal contingent of the London Natural History Society's Ecological Section undertook a systematic search for badger setts in the London area, which ran for about five years. The data from the survey were summarised in a (long overdue) paper by William Teagle to The London Naturalist published in 1969. The sightings logged up until 1964 showed badgers within what is now the M25 motorway, including in Richmond Park and Wimbledon Common, but none closer into the city than today's A205/A406/A1020 ring. Subsequently, many local mammal groups began reporting badgers in or around towns and cities across England during the 1970s, including Bristol, Bath, and Colchester. While many of these records were from suburbia, some were distinctly urban. In the mammal report for 1970/71, for example, the late Edwin Clements mentioned that Hastings was particularly well populated by badgers, with one growing sett in the centre of the town, while another was dug at the 19th hole of the promenade's putting green in Eastbourne, and a third (50-hole) within a built-up area of Brighton. Indeed, in his 1977 book Badgers, Ernest Neal wrote how badgers can become tolerant of man's encroachment on their domain and, under semi-urban conditions, “they are almost commensal of man”.
During 1981 and '82, Bristol University biologist Stephen Harris led a survey of badger activity in urban Britain, contacting households, the local government branches (e.g., councils, Ministry of Agriculture, Environment Heath, etc.), RSPCA, and local press/radio. Only towns and cities with a population of 20,000 or greater were included and, overall, data were collected from 378 local authorities. The results, published in Mammal Review in 1984, showed that very few towns and cities had established urban badger populations; those that did were mainly in south Essex, on the south coast (e.g., Brighton), or larger southern England cities such as Bristol and Bath.
The national 1985-88 survey identified only 10 setts (0.5%) in urban areas, while this had risen to 2.5% when the 1990s survey was conducted, and in more recent years we've seen an increase in the number of reports of badgers (and particularly the damage they cause) living in setts constructed in suburban and urban areas, such as parks and occasionally large gardens. Indeed, in their 2005 analysis of requests to interfere with badgers or their setts received by Defra between 1997 and 1999, A.J. Matthews and Colin Wilson noted that each year Defra receives about 700 complaints about problems caused by badgers (mostly damage to property) and the proportion from urban areas has been increasing, such that by the end of 1999 about one in five complaints were from urban areas. Again, however, we don't know whether this increase represents urban sprawl into badger territories, a broadening of habitat preferences in the face of urban expansion (i.e., badgers are adapting to living in proximity to people), an increased tolerance for human disturbance, declining human tolerance to wildlife disturbance, or a combination of these traits. There are certainly signs of adaptation, and data from a few small tracking and observational studies suggest urban badgers may be more sociable (i.e., less territorial) and live at higher densities than country-living animals. Whatever the root cause(s), there seems little doubt that we're more likely than ever before to bump into a badger while out and about in towns after dark.
Outside of Britain, there are some recent citizen science projects suggesting the slow colonisation of cities in Europe by badgers, including in Switzerland and Norway.
Sett site selection
Unsurprisingly, badgers look for certain kinds of habitat in which to construct their setts. As discussed above, many studies from across the Britain and Europe have shown that vegetation cover is usually the most important consideration, but soil type and gradient come a very close second.
Despite being proficient diggers, badgers tend to opt for more easily diggable soils, and the type of soil is a significant factor determining where they locate their setts. Clay, for example, is hard to dig, while setts built in peaty soil are more prone to becoming unstable and water-logged, meaning the residents must move more frequently than in other soil types.
In Yorkshire and Humberside, Middleton and Paget found that badgers preferentially chose sandy or chalky soils in which to dig their sets, and sand, magnesium limestone, and chalk together accounted for about 64% of the 836 setts recorded during their study. Similarly, Ernest Neal, in his1986 book, published an updated dataset of that originally collected by Edward Clements' in Sussex, which showed that, overall, chalky and sandy soils held nearly 90% of setts. Neal also noted how setts dug in sandy soils were much more extensive than those excavated in other soil types. Stephen Harris' Bristol study identified 65% of setts dug in sandy soils, while 26% were in limestone, and only just over 2% in clay, and, in the Republic of Ireland, Smal's survey found 28% in primarily sandy soils, 22% in loam and, surprisingly, 24% in clay soil. Smal's dataset reflects the observation that badgers will utilise clay if that's the only soil type available.
Badgers appear to prefer building setts on a slope, a very steep one if available. Middleton and Paget, for example, found that nearly 86% of setts were dug into a slope, while only 14% were on level ground. The data provided by Neal in Badgers suggest a similar value across the UK as a whole, with 88% of setts located on sloping ground, and even this masks the preference at a more local scale. Nearly all (95%) the setts found in Sussex were on a slope, for example. Interestingly, Neal noted that in most cases badgers don't show a preference for the direction the slope is facing, albeit that there is a tendency for clans in northern parts of Britain to choose warmer southern slopes. Similarly, there may be a preferred aspect if the setts are in particularly exposed areas. In an unpublished report on the status and distribution of badgers in Cornwall, compiled in 1970, for example, the late Dorset-born Cornwall Wildlife Trust president Rennie Bere noted how just over three quarters (77%) of setts found in the county faced away from the prevailing wet south-westerly wind.
Sloping ground may be selected by badgers for several reasons. Improved drainage is probably the primary advantage of building on a gradient, ensuring the sett is more likely to remain dry and warm, although in particularly steep locations, such as Welsh or Scottish mountain ravines, this probably also affords some protection against disturbance from both livestock and man. Additionally, as Tim Roper mentioned in his 2010 book Badger, suitable soil strata are more likely to be exposed on hillsides, while soil can also be more easily disposed of on sloping ground. Finally, Neal pointed out in Badgers that one can excavate a depth below ground that is well below ground-frost level rapidly when digging into a slope, and the resulting spoil heap that forms outside the entrance not only serves as a platform for the residents to sit and groom after emergence, but also:
“With continual excavations, the height of this platform increases above the level of the entrance, so the latter becomes the lower point of a kind of cone. This formation catches wind eddies from any direction, and a badger can detect danger without exposing itself fully.”