Inventory to follow the population dynamics of small rodents inluding voles (Clethrionomys glareolus* & Microtus agrestis), mice (Apodemus flavicollis & Apodemus sylvaticus) and shrews (Sorex araneus & Sorex minutus); *species dominates the catches all years. 20 Plots x 50 Traps x 3 Days (traps are checked for catches each day) in May and October each year (total 3000 trap days per season). Plots are distributed regularly over Grimsö Research Area (app. 13.000 ha). Data is presented in number of catches per trap nights (n(nights)=3).