Establishment, current status and possible origin of the greater white-toothed shrew Crocidura russula in Great Britain

Great Britain has three native shrews, while the greater white-toothed shrew (GWT: Crocidura russula ) is native to the European continent and some Channel islands. The GWT shrew was first reported in northern England in 2022. We detail its immediate investigation through national authorities, non-government bodies and individuals. Sixteen GWT were among 595 small mammals live-trapped. Barn owl pellet analysis revealed 56 GWT skulls in two areas. Genetic analysis of the cytochrome b gene suggests these population were derived from one or more continental European introductions, but not from the nearby island of Ireland where this non-native species has been present since at least 2007. The overall government response from the Department for Environment, Food and Rural Affairs and Natural England concluded that the species is too widespread to have any reasonable chance of eradication, but there remain ongoing efforts to determine the extent of invasion and its effect on native species.