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.