Monitoring use of runways by voles with passive integrated transponders

Abstract

We used passive integrated transponders (PIT tags) to mark individual voles (Microtus ochrogaster and M. pennsylvanicus) and to monitor their activity in runways. We marked 893 voles with both PIT tags and ear tags between July and November 1993, and recaptured gig of these. Over 95% (778) of recaptured voles retained an active PIT tag until their last capture, an average of 7 weeks after initial capture. One-half as many PIT tags (40) as ear tags (88) was lost. We monitored the activity of individual voles by placing circular antennae linked to PIT-tag readers across runways. Typically, three or lout voles used the same runway during a 24- h period. Voles were most active near sunset and sunrise. We conclude that an automated system based on PIT tags can provide reliable, detailed information on the spatial pattern and timing of activity for individual voles.