Performance of passive integrated transponders (PIT tags) as a marking system for common brushtail possums Trichosurus vulpecula - a cautionary tale.

Abstract

Passive integrated transponders (PIT tags) have been used to mark many vertebrates and in this study 196 Trichosurus vulpecula were fitted with a Trovan ID-100 PIT tag when first captured for DNA studies using tissue samples from the ear pinnae. Not all individuals were recaptured but evidence based on a hole, scar or tear in the ear, presumably form previous tissue sampling, suggested 17 PIT tag failures. In 6 individuals a PIT tag was palpable under the skin at the place of insertion. In 3 animals the PIT tag malfunctioned after 5-16 months despite working on previous recaptures. Of the 17 suspected malfunctions, 13 could be verified as recaptured individuals through genotypic matching. The remaining 4 suspected failures could not be matched genotypically and were considered to be newly trapped. A back-up mehtod, such as tattooing or genetic tagging, should be considered.