Number of the burrow entrances (A) and the depth of the nest (B) of vole females (Microtus arvalis) in the presence of a nest predator (NP, Greater white toothed shrew, Crocidura russula), or a interspecific resource competitor (RC, female field vole, M. agrestis) or a intraspecific competitor control (C, female common vole, M. arvalis). All burrow entrances were counted at day 22 of the experiment when vole nestlings were 3 days old. Please note that the y axis in (B) is negatively scaled (0 = ground level), visualizing the direction of digging into the ground.
Liesenjohann et al. BMC Ecology 2013 13:33 doi:10.1186/1472-6785-13-33