European Hedgehog Habitat
Hedgehogs, as their name implies, are found in hedgerows as well as on farmland and in copses, particularly in bushy and shrub-rich habitats. They are also found in woodland, particularly at the periphery, in parks, gardens and on sand dunes. Mixed pastureland, composed of many small well-hedged fields with livestock, and deciduous copses are ideal habitat for hedgehogs.
We know from tracking studies that hedgehogs prefer edge habitats and can frequently be found along linear features (woodland edges, hedgerows, roadside verges, etc.) and tend to avoid arable land. Radio-tracking hedgehogs in Nottinghamshire between 2008 and 2015, for example, Richard Yarnell at Nottingham Trent University found a clear association with pasture land and buildings on campus and a clear avoidance of arable fields. Similarly, during her Ph.D. studies at Oxford University, Carly Pettett observed that hedgehogs were rarely found in arable land, or woodlands containing badger setts. Presenting her preliminary findings at The Day of the Hedgehog conference in 2015, Pettett suggested that rural villages were important for sustaining hog populations in arable land.
Interestingly, Ireland may represent an exception to the broad rule that hedgehogs dislike arable land. Amy Haigh and colleagues at University College Cork observed that hedgehogs actively selected arable land, moving away from gardens to spend most of their time there after the crops were harvested in September; these areas had the highest invertebrate (food) densities. In their paper to Mammalia in 2012, Haigh and her co-workers suggest that the thicker hedgerows, which include bramble, as well as the presence of horses in some of the arable fields (with their dung adding to the soil nutrient content) accounted for the increase in invertebrates in these areas relative to arable land elsewhere. Indeed, data collected by Anouschka Hof and Paul Bright from the north coast of Norfolk show a clear trend for hedgehogs to be found in hedgerows and agri-environmental field margins (i.e. strips around the edge of fields that aren’t sown with crops, being left to ‘grow wild’ instead). In their paper to Animal Conservation during 2010, Hof and Bright conclude:
“The implementation of agri-environment schemes that include wide field margins and dense, well-established hedgerows on farmland could significantly contribute to the viability of hedgehog populations in intensive arable-farming landscapes …”
These areas may not just be attractive to hedgehogs; they may help hedgehogs get around, too. Writing in the journal Biological Conservation in 2014, Tom Moorhouse and colleagues described how, in their computer model, doubling the amount of hedgerow from 25% to 50% resulted in half of their hedgehogs moving an extra 2km (1.2 miles), enhancing population connectivity.
Hedgehogs are also found in urban gardens, on amenity grassland (e.g. parks, sports fields, village greens, recreation grounds, etc.) and ‘waste ground’ in our villages, towns and cities. Some earlier authors, Konrad Herter in his 1965 book Hedgehogs for example, have suggested that high urban populations were a result of escaped or released pets and animals introduced for pest control purposes. This is an interesting theory because, although we know hedgehogs can move a kilometre or more in a single night, we have very few data on their dispersal preferences.
During her Ph.D. studies at Oxford University, Carly Pettett suggested that spill-over from rural villages may be important in sustaining hedgehog populations in surrounding arable land, but studies by Has Kristiansson in southern Sweden and Pauline Hubert and colleagues in France failed to find any evidence that hedgehogs dispersing out of rural areas into urban ones made any significant contribution to the higher urban densities. Some authors have suggested this preference for urban areas may reflect a combination of increased resources, with people actively feeding hedgehogs as well as maintaining gardens that provide natural foraging and nesting opportunities, and relative safety from predators; namely badgers.
We know badgers have a significant potential to affect hedgehog activity and distribution (see QA). An analysis of the badger culling trial data by Iain Trewby and his colleagues, published in 2014, found hedgehog densities in the cull areas increased as much as five-fold over those in areas where badgers weren’t culled and, in Oxford, Thierry Micol and his team found that farms with hedgehogs tended to be those without badger sets. In their 1996 opus on the badger, Ernest Neal and Chris Cheeseman note that hedgehogs tend to be predated by badgers away from urban areas, where badger activity is generally higher, spawning the idea that urban and suburban areas may offer hedgehogs a refugia from badger predation.
Studies attempting to correlate urban hedgehog abundance with badger density have, however, produced mixed results. Working in the Netherlands, Jeike van de Poel and colleagues found that badger presence could broadly be used to predict hedgehog presence and that urban areas had a positive effect on hedgehog numbers but a negative one on badgers; the authors suggest that Dutch hedgehogs are primarily found in urban areas because they’re avoided by badgers. During their study in north-eastern France, however, Pauline Hubert and colleagues failed to find any significant effect of badger density on hedgehog abundance in the urban area of their study site, although they do note that continental badger populations are low. In their study area, van de Poel and his co-workers identified some habitats that were good for both badgers and hedgehogs, suggesting the creation of a diversity of natural habitat in an environment may help keep the two species apart. Indeed, there is a growing pool of data to suggest that both species may coexist where food is abundant, and it may be this aspect, more than any specific avoidance by badgers, that allows hedgehog numbers to increase in urban environments. Certainly, the data presented by Hubert and her team suggest that food (earthworms and pet food) was a better prediction of hedgehog abundance than badgers.
Hogs are conspicuously absent from marshland and open moorland and records are sparse from areas of dense pine forest, although there is a population in the Alps, where they persist in the mountain pine (highest) treeline some 2,100 m (6,900 ft.) above sea level. Their apparent penchant for dry areas with plentiful nesting materials probably explains their typical absence from damp woods, marshes and conifer plantations, although hedgehogs have been observed to build nests from pine needles and thrive on the invertebrates found in conifer forests.