Interspecific competition in the shrews Sorex araneus and Sorex minutus (Soricidae, Insectivora): a population study of the Irish pygmy shrew

Sorex araneus and S. minutus , which are likely to show a temporary vertical habitat segregation, are largely sympatric, except in Ireland, where S. minutus occurs alone. Two mechanisms for this segregation may be suggested: a direct interspecific interaction or an evolutionary fixed relationship.
Population densities and surface activity were measured, both in areas where the two species occur together (The Netherlands) and in areas in Ireland, in (order to investigate the possibility of a habitat shift and its influence on population density. No such effect was found in the present study.