Artificial supplementary food influences hedgehog occupancy and activity patterns more than predator presence or natural food availability

Abstract

Supplementary feeding for declining hedgehog Erinaceus europaeus populations is popular in Great Britain and has been suggested as an important factor in explaining higher densities in urban areas compared with rural ones. Occupancy modelling was used to test whether spatial variation in supplementary feeding, natural food, habitat, or predator presence best explained patterns of hedgehog occupancy and diel activity. Supplementary food and urban habitats had a strong effect on hedgehog occupancy and detection, with all supplementary feeding sites recording hedgehog presence. Natural prey availability and the presence of predators was relatively higher in rural areas, and although the top-ranked occupancy models (AIC < 2) contained natural food and predator covariates, the strength of these relationships was negative and non-significant. This suggests local hedgehog site use is influenced by access to artificial supplementary feeding in urban areas. There was no significant difference in diel activity overlap between rural, urban, and urban feeding sites, but peaks in activity early in the activity period suggest preferential access to feeding site by hedgehogs compared with later in the evening. This is the first study to show the importance of supplementary feeding as a covariate of hedgehog occupancy in relation to natural food availability, and we recommend that future studies quantify supplementary feeding in population and distribution studies of urban mammals.