Although it’s rare to see one of these secretive animals on our streets, the UK’s largest land carnivore – the badger – makes itself at home in urban graveyards, gardens and allotments.
But little is known about urban badgers compared with their rural relatives.
Finding a suitable site for digging setts appears to be the biggest limiting factor on where badgers occur in cities and how big their populations are
But researchers at the University of Brighton hope tracking badgers (Meles meles) in the city using GPS collars will build a clearer picture about how the striking mammals cope with city living.
The study, led by Dr Dawn Scott, is being featured on BBC Two’s Autumnwatch.
One major finding revealed through mapping the movements of seven collared urban badgers is that these animals stick to tiny areas.
“So far we have found that badgers are broadly distributed in all parts of the city of Brighton and Hove [and] that their territories [or] home ranges are very small (about 5 hectares),” says Dr Bryony Tolhurst from the University of Brighton, who is studying Brighton’s badgers alongside Scott.
In contrast, rural badgers’ home ranges are 50 hectares on average, but when food is scarce this can increase to over 300 hectares.
According to the team’s data, one GPS collared female badger in Brighton, named Cherry, moved within a 200m by 100m (656ft by 328ft) area around her sett’s city graveyard location.
We want to know whether people feeding badgers affects the size of badger home ranges
Another Brighton badger, called Lottie, had a similarly small range, using the allotment where her sett was and about 25 neighbouring gardens to find food.
Graveyards and allotments alongside gardens, parks, waste grounds and playing fields are typical locations for urban badgers’ homes. They live “everywhere and anywhere”, says Tolhurst.
“They require a slope to dig their sett into, ‘workable’ soil and a bit of cover… Finding a suitable site for digging setts appears to be the biggest limiting factor on where badgers occur in cities and how big their populations are.”
Roads are one hazard appearing to limit urban badgers’ territories.
But research has shown these city dwellers have a looser territorial structure, consisting of small territories overlapping with other setts.
Other differences between city and country badgers include the size and weight of their clan, or family group.
Family group size tends to be smaller for urban badgers, which average about five or six animals, while in rural places, up to about 30 badgers can live in a main sett. And previous research has shown city badgers use fewer secondary setts, perhaps due to lack of available space.
City badgers’ increased size could be down to easy access to “human food” that is either scavenged or put down for them.
For example, one collared badger in the study named Plum, filmed by the Autumnwatch crew in her garden home, weighs about 13kg (29lb), according to the Brighton researchers, while the average weight for badgers in autumn is about 11-12kg (24-26 lb). Both urban and rural badgers, though, are at their heaviest in the autumn when they store up fat ahead of winter.
The team in Brighton hope GPS collars will help them reveal more about urban badgers’ food preferences and whether deliberate feeding affects how they use their territories.
“We want to know whether people feeding badgers affects the size of badger home ranges,” Tolhurst says, explaining the team postulates that regularly-fed badgers will use a much smaller area than ones that aren’t fed, “because as a general rule, badgers will not roam further than is necessary to find enough food to sustain themselves”.
Although badgers are classified as carnivores, with their diet mainly consisting of worms, they are opportunistic foragers and also eat small mammals, berries, fruit and scavenging human food they find or that’s been put out for them.
Tolhurst says tracking collars are the best way to monitor the badgers’ movements in fine detail. And that the team also want to find out if there are differences between how suburban and inner city badgers use their territory and where the action hot spots are in these ranges.
The study started in 2014 and is part of a larger urban mammal monitoring programme which started in 2012, and has tracked hedgehogs and foxes.
Previously, the team tracked a fox named Fleet making a record-breaking 40 mile (70km) journey.
And the study has also discovered that more cities have foxes compared with 30 years ago.
It’s currently unknown whether badgers have actively moved to our cities, or whether they have been forced to adapt as urban areas have sprung up around them.
But the study in Brighton could unlock secrets to how well badgers are doing as they negotiate this changing world.
Autumnwatch airs on Monday 2 November at 21:00 on BBC Two, and at 20:00 Tuesday to Thursday. But don't forget to tune in live on the website and Red Button with Unsprung, Extra and, of course, the famous webcams.
Follow #Autumnwatch on Facebook, Twitter, Instagram and Flickr groups for exclusives, quizzes and how to get involved using #MyPatch and #BeatBrett and get the latest news about the urban badgers by using the hashtag #SettsInTheCity
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