By Bill Bateman & Trish Fleming. Of all the species described as ‘urban adapters’, it is perhaps the red fox (Vulpes vulpes) that is most well-known.  In Europe, foxes seem to have been hanging around towns and cities for centuries – certainly urban foxes were recorded around London in the 1800s [1].  Today, the red fox has been recorded in over 114 cities across the globe [2] including Perth, here in Western Australia.

Foxes spread across the continent since being introduced into eastern Australia in the 1860s.  Foxes seem to have reached the west on their own, first recorded west of Kalgoorlie in 1918, having apparently ‘surfed’ across the Nullabor on a ‘wave of rabbits’ – a favoured food.

In Australia, it is common knowledge that foxes are bad news for our native wildlife. We tend to think of this as happening out in the bush or in the farmlands. However foxes seem to do quite well in towns.

Foxes require both secure daytime rest sites and breeding sites (earths) [3], and even in towns, red foxes probably need to dig earths for denning.  Patches of green space or wasteland will be important to them but foxes can also breed under the floorboards of occupied houses and derelict buildings in Bristol, UK [4].  In the USA, all sorts of shelters, including road culverts and old barns, provide shelter for red foxes [5].

In Australia, foxes often use the thick growth of non-native plants such as lantana and blackberry in which to rest [6].

Roads can be a problem for any urban wildlife. Research in the UK showed that foxes avoided roads at their busiest times prior to midnight, and only crossed roads when they were much safer [7].  Green corridors along power lines and streams and city parks also probably make safe routes for foxes.

Foxes will eat a broad range of food types and can also adapt to substantial local variation in food types available: in other words, they will eat anything that is available, regardless of where they are.  Foxes love fruit, such as mulberries, grapes and figs and will eat insects and other invertebrates.  More than half of the stomach contents of red foxes in central Zurich, Switzerland, was out of rubbish bins, especially fried chicken! [8].  Refuse is a constant source of food and means that urban foxes may have access to an increased range of high nutrition food as well as a greater degree of seasonal food security than do rural foxes.

All this food means that fox densities of up to 37 individuals/km² have been recorded in the UK [9], and 16 individuals/km² were recorded for Melbourne Australia [10].  Not only that, but a constant supply of high quality food may have an effect on the very appearance of urban foxes: a pattern of size increase in skull measurements has been recorded for  fox populations in Denmark from 1862 to 2000, over which time there was an increase in access to human-sourced food sources [11].

 

But cities are not all good news for the fox.  Road kill and direct human control is probably the biggest cause of death for the urban fox.  In a review of urban carnivores [12] we found that road accident was a major cause of mortality in carnivores, responsible for up 40% of recorded fox deaths.  This may be particularly bad for juveniles that are dispersing [7].

So, how do we find out more about urban foxes?  Researchers at Murdoch and Curtin Universities have begun a project involving putting GPS collars on urban foxes to better understand how they use the urban matrix in Perth.  Soon we will also have a better idea of what they are eating in the city, and how they avoid humans and other dangers.  Who knows if foxes are here to stay? It is up to us to find out more about them across the many habitats they are able to survive in.

1. Teagle, W.G., The fox in the London suburbs. London Naturalist, 1967. 46: p. 44-68.
2. Soulsbury, C.D., et al., Red foxes (Vulpes vulpes), in Urban carnivores, S.D. Gehrt, S.P.D. Riley, and B.L. Cypher, Editors. 2010, The John Hopkins University Press: Baltimore. p. 63-75.
3. Baker, P.J., et al., Flexible spatial organization of urban foxes, Vulpes vulpes, before and during an outbreak of sarcoptic mange. Animal Behaviour, 2000. 59(1): p. 127-146.
4. Harris, S., An estimation of the number of foxes (Vulpes vulpes) in the city of Bristol, and some possible factors affecting their distribution. The Journal of Applied Ecology, 1981. 18: p. 455-465.
5. Gosselink, T.E., et al., Survival and cause-specific mortality of red foxes in agricultural and urban areas of Illinois. Journal of Wildlife Management, 2007. 71(6): p. 1862-1873.
6. Marks, C.A. and T.E. Bloomfield, Home-range size and selection of natal den and diurnal shelter sites by urban red foxes (Vulpes vulpes) in Melbourne. Wildlife Research, 2006. 33(4): p. 339-347.
7. Baker, P.J., et al., Activity patterns of urban red foxes (Vulpes vulpes) reduce the risk of traffic-induced mortality. Behavioral Ecology, 2007. 18(4): p. 716-724.
8. Contesse, P., et al., The diet of urban foxes (Vulpes vulpes) and the availability of anthropogenic food in the city of Zurich, Switzerland. Mammalian Biology, 2004. 69(2): p. 81-95.
9. Baker, P.J., et al., Differences in the capture rate of cage-trapped red foxes Vulpes vulpes and an evaluation of rabies control measures in Britain. Journal of Applied Ecology, 2001. 38: p. 823-835.
10. White, J.G., et al., Home range, habitat selection and diet of foxes (Vulpes vulpes) in a semi-urban riparian environment. Wildlife Research, 2006. 33(3): p. 175-180.
11. Yom-Tov, Y., S. Yom-Tov, and H. Baagøe, Increase of skull size in the red fox (Vulpes vulpes) and Eurasian badger (Meles meles) in Denmark during the twentieth century: an effect of improved diet? Evolutionary Ecology Research, 2003. 5: p. 1037-1048.
12. Bateman, P.W. and P.A. Fleming, Big city life: carnivores in urban environments. Journal of Zoology, London, 2012. 287: p. 1-23.