Urban foxes: Numbers
The total number of foxes living in British cities is not known as there are no recent estimates. Sarcoptic mange, a disease that affects foxes, has spread throughout Britain and caused a decline in fox numbers in many areas. In contrast, foxes have expanded in some other areas such as eastern England.
The last estimate available of 33,000 adult foxes in urban areas at the end of winter (i.e. just before the cubs are born) dates back to the 1980s but it is probable that declines following mange and expansions into new areas cancel each other out and that urban fox numbers are little changed in Britain as a whole. If we add this number to the number of foxes estimated in rural environment, the total number of adult foxes in urban and rural Britain is about 258,000 at the end of the winter. Each year approximately 425,000 cubs are born in spring.
The timing and reason of colonization
Foxes first started to colonize British cities in the 1930s but only since the Second World War have they become common. Certainly, by the late 1940s foxes were common in the southern suburbs of London. In other cities, such as Cambridge and Norwich, colonization has been more recent.
A common myth says that at the beginning of the 1950s, following the epidemic of myxomatosis which decimated rabbit populations in the British countryside, foxes were starving as rabbits had disappeared and, as a result, moved into cities. This is untrue and in any case urban foxes were already well established. It is much more likely that as cities grew larger, parts of the countryside immediately surrounding the urban areas became enclosed and foxes (and other animals) living there came into closer contact with humans. This happened long before myxomatosis arrived.
This process was facilitated in those cities where semi-detached houses with medium-sized backgardens were common. In fact, foxes seem to prefer those cities and suburbs with medium to large size backgarden, which provide all the diverse array of food, cover during the daytime and den sites (hedges, scrub, compost heap, sheds) that the foxes need. In addition, if stray dogs are absent from these areas of low density-housing with medium to large backgardens, this is an added advantage for foxes. Stray dogs compete with foxes for food and can even kill foxes.
Which cities have foxes?
In Britain foxes are very common in those cities with residential areas of the type built in the 1930s, which have medium to large size back gardens. There are fewer foxes in large industrial towns and in modern housing developments with small back gardens. The lack of gardens of suitable size, which provide cover for the foxes to hide during the day, is also the reason why foxes are rare in some European cities.
Urban foxes are common throughout England and becoming increasingly common in South Wales. In Scotland they are also widespread: Aberdeen, Dundee, Edinburgh, Glasgow and many other towns and cities have urban fox populations.
Historically urban foxes were thought to be uniquely a British phenomenon, but in the past twenty years they have been reported in many major European cities e.g. Aarhus and Copenhagen in Denmark, Paris in France, Berlin and Stuttgart in Germany, Rome in Italy, Oslo in Norway and Geneva and Zurich in Switzerland.
Foxes have also been reported in many cities and towns in Australia (Adelaide, Brisbane, Canberra, Melbourne, Sydney), Canada (Toronto), Japan (Sapporo) and the USA (e.g. Los Angeles, New York, Washington).
Question & Answer
TopAre fox numbers increasing in cities?
This is a difficult question to answer. Foxes are colonising some cities in Europe and in Britain. In some other cities however, sarcoptic mange has severely reduced fox numbers. Depending on which British city we consider, and how long ago mange reached that urban area, fox numbers might be increasing, decreasing or showing no change. Overall, however, it is probable that these changes balance each other out and the total number of urban foxes in Britain is probably much the same as a decade ago.
TopCan fox numbers be reduced?
It is a misconception that fox numbers can actually be controlled. To reduce fox numbers, at least 70% need to be killed each year and every year for a long time. This is fairly obvious: typically, a pair of foxes produces 4 or 5 cubs a year, so if you kill four foxes during the year i.e. 67%, you still have a pair left to start again the next breeding season.
In the 1800s fox numbers were probably reduced in East Anglia and the east coast of Scotland by widespread poisoning and trapping with leghold (gin) traps. Both of these activities are now illegal. However, the widespread and indiscriminate use of traps and poisons (both techniques killed many other species of birds and mammals) over a long period will reduce fox numbers. Fox "control" was probably also more effective because there were far more gamekeepers and others involved in fox control, and so they operated over large areas. Today, there are far fewer gamekeepers, and much smaller areas are subjected to fox control. This means that it is far more difficult to reduce fox numbers, other than temporarily and locally.
In many different urban areas control has been attempted unsuccessfully (see the case of London), in no small part because, whilst some people want the foxes killed, the vast majority do not. So whilst a few foxes may be killed, they are rapidly replaced by foxes from the surrounding area, often literally within days. This poses a serious problem where foxes are invasive species, as in Australia.
- Gloor, S., Bontadina, F., Hegglin, D., Deplazes, P. & Breitenmoser, U. (2001) The rise of urban fox populations in Switzerland. Mammalian Biology 66, 155-164.
- Harris, S., Morris, P., Wray, S., & Yalden, D. (1995) A review of British mammals: population estimates and conservation status of British mammals other than cetaceans. Joint Nature Conservation Committee, Peterborough.
- Baker, P. & Harris, S. (2001) Urban foxes. Whittet Books, Suffolk.
- Marks, C.A. & Bloomfield, T.E. (1999) Distribution and density estimates for urban foxes (Vulpes vulpes) in Melbourne: implications for rabies control. Wildlife Research 26, 763-775.