A New Application for Transponders in Population Ecology of the Common Tern

Abstract

We injected transponders subcutaneously to mark single Common Tern (Sterna hirundo) adults and all chicks of a colony at Wilhelmshaven with the aim of establishing a completely marked colony. We present details on the equipment and methods and report preliminary results. Microtagged terns can be identified for life, not only at their nest when breeding, but also at resting places by fixed antennas at distances of < 11 cm. Thus, nonbreeders can be identified as well. We also weighed terns remotely to obtain information on their body condition. Body mass data as well as identification codes were electronically stored. Preliminary data indicated that adult survival was ≥ 87% and subadult survival until age two was ≥ 20%.