Badgers live underground in a network of tunnels and chambers known as a sett.
Setts can have anything from 1 to 30 or more entrances, often with conspicuous spoil heaps nearby as evidence of badgers’ prodigious digging.
The number of badgers in a sett varies greatly. Unfortunately, there isn’t a correlation between number of entrance holes and number of animals, as the same badger may use a variety of holes at different times.
Sett surveyors in Berkshire are often rewarded with big piles of orange sand or chalky rocks as a clue to badger activity.
Sett entrances are at least 25cm wide and some 20cm high. The sideways D shape created looks, unsurprisingly, like the shape of a badger in cross-section.
Inside the sett, tunnels slope downwards but don’t normally descend by much more than a couple of metres. They can, however, extend across a large area.
Nesting, or sleeping, chambers are usually small to help the badger stay warm, especially important in Winter when body fat needs to be conserved.
Sometimes we see bedding strewn outside the sett entrance where the badgers have dragged it out to dry and to kill off parasites.
Chambers are lined with plant material for bedding which badgers collect and endearingly drag backwards into their sett.
As well as providing comfort, bedding is also thought to be used for the disinfecting properties it offers. Amazingly, too, it would seem that badgers create underground radiators by storing decaying plant material in their chambers!
Well worn paths or chalky footprints may be evident near setts, both between entrances and heading away, giving clues to the clan’s nightly forays. Badgers are creatures of habit, following the same runs year after year.
Where are badger setts found?
Most badger setts are found in deciduous woods, with 90% on slopes or in the steep banks of footpaths and railway embankments, drainage being essential. Disused pits are also a favoured location, with Berkshire having a number of badger-inhabited clay and chalk pits.
But badgers are adaptable and we do know of setts even in the heart of Reading, Newbury, Maidenhead and other urban areas of Berkshire. Indeed, our Binfield sett is surrounded by housing.
Badgers are territorial, defending their home patch against intruding rivals.
The territory may include separate but close ‘annexes’ or ‘subsidiary’ setts in addition to the 'main' sett. These will be used by the same clan but are not connected underground to the main sett. Single entrance holes, known as 'outliers', may also be found within a territory and may be used as boltholes if disturbed whilst foraging. Whilst main setts are in use all year round, other sett types may not be in constant use.
The size of the territory is mainly affected by food availability. A badger clan in Reading able to forage from bins and gardens may therefore have a smaller territory than a clan in an area characterised by commercial timber and fewer feeding opportunities.
‘Boundary latrines’ also help to mark the edge of a territory, with a neighbouring clan using the same latrine to indicate acceptance of boundaries.