Continuing influences of introduced hedgehogs Erinaceus europaeus as a predator of wader (Charadrii) eggs four decades after their release on the Outer Hebrides, Scotland
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Non-native predators can cause major declines or even localised extinctions in prey populations across the globe, especially on islands. The removal of non-native predators can, therefore, be a crucial conservation management tool but there can be challenges when they are viewed as charismatic in their own right. Four decades after their introduction to islands in the Outer Hebrides, Scotland, European hedgehogs Erinaceus europaeus continue to be an important nest predator for a declining population of breeding waders. Where hedgehogs were rare, clutch survival rates (assessed using nest temperature loggers) of five species of waders (dunlin Calidris alpina, lapwing Vanellus vanellus, redshank Tringa totanus, snipe Gallinago gallinago and ringed plover Charadrius hiaticula) were higher than where hedgehogs were relatively more abundant. Hedgehogs were the most frequent nest predator identified using cameras. However, factors influencing population sizes of breeding waders are complex and unlikely to be attributable to a single species of predator. The interactions between predation, land use, habitat and the changes in each deserve further attention.
KeywordsPredation Shorebird Non-native Machair
This study was commissioned by Scottish Natural Heritage and we are grateful to Des Thompson, Ian Bainbridge, Iain MacLeod, David MacLennan and Gwen Evans for their support. We are especially grateful to all the crofters and grazing clerks who facilitated the fieldwork. Fieldwork was managed by Charles Thompson and undertaken by Andrew Airnes, Stephen Bentall, James Bray, Christian Christodoulou-Davies, Terry Fountain, Liza Glesener, Susan Holoran, Colin Kerr, Mairi MacCormick, Andy Roberts, and Yvonne Townsend, with additional nest finding support from other SNH staff in the Argyll & Outer Hebrides Unit, in particular Flora Donald and Patrick Hughes. Further advice was provided by Ruth Mitchell (JHI) and members of Scottish Natural Heritage’s Scientific Advisory Committee and Expert Panel, especially Nicholas Aebischer, Chris Spray and Colin Shedden. The manuscript was improved by the comments of two anonymous reviewers.
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