The Survival and Welfare of Hedgehogs (Erinaceus Europaeus) After Release Back into the Wild
The fate of rescued hedgehogs (Erinaceus europaeus) released back to the wild has now been the subject of several follow-up studies. Although subject to various hazards, released hedgehogs have clearly shown essential 'life-skills '. However, all previous studies have involved
releases into hedgehog-rich areas and the observed long-range (≥500m) dispersal movements shown by some subjects, of up to 5km, may be a consequence of local intraspecific competition. This study has reduced a number of potentially confounding subject variables and provides follow-up data
on 12 age-matched female hedgehogs with similar histories. A main group (n = 10) was released into a rural woodland area (Surrey, UK) of low natural hedgehog density, and radio-tracked for up to 108 days. A pilot release of two animals in an urban area with an established hedgehog population
also took place (tracked for 109 and 131 days respectively). Most of the main group dispersed (up to 3km) from the release site; the two animals in the urban site did not. These data, taken with those from previous studies, suggest that dispersal is not specifically the result of intraspecific
competition. Overall survival at week 8 was 42 per cent (5 hedgehogs) plus two lost animals. This is comparable with previous studies. However, survival fell to 25 per cent (3 animals) plus two lost animals by week 15. Of seven recorded deaths, only one was the result of a failure to thrive
and all other mortalities were accidental: four road deaths, one drowned in a pond and one predation. The study concludes that the hazards of the human environment were the principal threat to the welfare and survival of released hedgehogs in the area.