Passive Integrated Transponders for Marking Free-Ranging Townsend's Ground Squirrels

Abstract

We tested passive integrated transponders (PIT) as a technique for marking free-ranging Spermophilus townsendii individually and permanently. We marked 1,179 squirrels with PIT tags. No known mortalities were caused by PIT tagging, and we observed little incidence of infection at the implant site. Rates of PIT-tag loss probably were <0.05 within 1 year, with most tag loss happening shortly after tagging (≤10 days). We detected no tag losses between 2 years. We conclude that PIT tagging should be considered as an alternative to ear tagging and toe clipping for marking small mammals. PIT tagging may especially benefit long-term demographic studies intended to estimate rates of annual survival.