What causes a rise in the fox population?
Patrick Hook takes a look at how the cull of one predator leads to the growth of another
Those of us who live where there’s been a badger cull may well have noticed a large increase in the fox population since it ended. Countless farmers have commented something or other on the matter, and I suspect that to many it looks as though we, the local shooters, haven’t been doing our job properly. That really isn’t the case though, as evidenced by several recent scientific studies on the subject. They all agree that wherever the badgers have been culled, foxes subsequently prospered.
Due to regional variations, there are no hard and fast rules as to just how many more foxes there will be. These include such factors as the availability of food, the weather and local pest control. A rough estimation suggests that their numbers can more or less double, as shown by biologists at the Central Science Laboratory in York. Some researchers claim that the removal of badgers increases the fox population by an average of one extra fox per square kilometre, but others say as many as two.
Since the increase in vulpine populations has been observed and recorded in so many places, one has to accept it as fact. This then raises two basic questions.
First, why have their numbers increased so dramatically? Second, what are the consequences likely to be? Let us address the probable causes first, but before doing so it’s worth mentioning that nobody actually knows for sure.
My own opinion is very much in line with the published studies, in that there are three main reasons.
The first of these is that when badger setts become vacant, a lot more holes are available for foxes to breed in. It’s worth bearing in mind that most badger territories typically contain multiple setts that they‘ll move between to suit their purposes. For instance, one collection of holes may be sited next to a maize field that only gets used while the field is ripe. The rest of the year it will therefore appear to have been abandoned, when the reality is that it was only ever a part-time habitation. Some setts may be hundreds of years old and can stretch for significant distances. I know of one hill that is so interlaced with tunnels that it’s like Swiss cheese.
Although there are lots of accounts of them sharing holes with foxes, the reality is that not many badgers will tolerate them on their patch. For this reason, when their numbers are reduced it provides more breeding opportunities for Charlie.
The second factor is that both foxes and badgers are opportunists that will scavenge, harvest or kill and eat whatever they come across. Their prey can range from small creatures like crane flies right up to birds and mammals like lapwings, skylarks, pheasants, hares, rabbits, lambs and so on. Fewer badgers means more food for foxes, which leads to more breeding success. Although the matriarchal vixen produces the first litter, if there is enough food it will allow one or more of its subordinates to have young later on. In plentiful years, there may be as many as three broods from a single fox group.
The third component concerns the extent to which badgers kill fox cubs. Although I’ve witnessed badgers and foxes rubbing heads while feeding, the former will usually chase the latter off if they get the chance. I remember playing a fox cub sound on my caller one time, when I spotted a badger steaming over the hill towards us. It ran down the valley, jumped a stream and forced its way through a thick hedge. It furiously charged the caller, rugby-tackling it. As soon as the badger scented a human, however, it did an abrupt backwards somersault and made its escape.
An increased vulpine population is not good for our native wildlife. The bottom line is that those of us who shoot foxes can’t let up. I consider wildlife protection one of my main motivators and rejoice in seeing the fruits of my labours in the form of hares, skylarks, hedgehogs and so on.
Patrick’s top tips
- If you want to know how many foxes are in your patch, a good way to find out is to put some bait down. Roadkill is ideal. Doing this will draw the foxes to a given spot. Once they’ve found the roadkill and have started eating it regularly, put a trail camera focused on the relevant area for a few nights. You may be surprised at just how many there are.
- Don’t forget that badgers are covered by the Protection of Badgers Act 1992, which makes it illegal for anyone to shoot or disturb them unless they have a government-issued licence. More info on this can be found at legislation.gov.uk/ukpga/1992/51/contents
- The GWCT has some interesting information about the need for controlling foxes to protect waders. It can be found by going to its website at gwct.org.uk/wildlife/research and following the ‘birds/waders’ link in the left column at the bottom.