Diet of hedgehogs (Erinaceus europaeus) in the upper Waitaki Basin, New Zealand: Implications for conservation

European hedgehogs (Erinaceus europaeus) have recently been identified as a conservation threat in New Zealand. Hedgehogs were kill-trapped at 14 wetland and braided riverbed sites in the upper Waitaki Basin between late October 1997 and early February 1998 and their gut contents described. The most commonly eaten prey were Coleoptera (present in 81% of 192 guts), Lepidoptera (52%; n = 192), Dermaptera (49%; n = 192), Hymenoptera (42%; n = 192) and Orthoptera (31%; n = 319). Large numbers of single invertebrate prey types were frequently eaten by individual animals, likely indicating hedgehogs’ ability to take advantage of rich patches of food. Weta remains occurred in 22% of guts, with the gut of one adult male containing 283 Hemiandrus legs. No remains of the endangered robust grasshopper were found. Eggshell was recorded in 4% of 615 guts. Native lizard remains were found in 6% of 615 guts and three times as many adult female hedgehog guts contained lizards compared with adult males. This difference may be linked to females’ high energetic demands during the breeding season. The dependence of hedgehogs on invertebrate prey is likely to have significant implications for the conservation of threatened endemic invertebrates, which often show restricted ranges. While birds’ eggs and native lizards appear to be of lesser importance, small, localised populations of these fauna may still be threatened by hedgehog predation.