FATES OF FOSSORIAL WATER VOLES, ARVICOLA-TERRESTRIS, AS REVEALED BY RADIOTELEMETRY

The fates of 94 fossorial water voles were studied in Switzerland from 1984 to 1986 using radiotelemetry. Fifty-six individuals were recaptu red on the study plots at the end of the radiotracking sessions. Takin g into account that 34 individuals either died, dispersed or were kill ed by predators, the fates of 95.7% of the voles could be assessed, as compared to only 59.6% if losses were tallied by classical capture-re capture analysis. In most cases, death in situ (10 cases) could be dis tinguished from the 13 recorded cases of predation (including 4 cases of predation on dispersers). Only 4 tags (4.3%) were lost. Moreover, t he position of the tags and the marks left on the radio-collars allowe d the identification of mammalian and avian predators in most cases of predation. Finally, the fates of the 15 dispersers could also be asse ssed.