IMPLANTED TRANSPONDERS IN PENGUINS - IMPLANTATION, RELIABILITY, AND LONG-TERM EFFECTS

Subcutaneously implanted transponders have proved to be a reliable mea ns of identifying individual penguins. We found survival of Adelie Pen guins (Pygoscelis adeliae) carrying transponders over five seasons to be equal to or better than that of birds with flipper bands, although not statistically significant on an annual basis. There were, however occasional problems associated with the use of implanted transponders. The transponder removed from one bird had developed a slimy biofilm h arboring potentially pathogenic organisms incorporated at the time of implantation. If such contamination is common, it is possible that the long-term survival of groups of birds carrying implanted transponders may be lower than that of unmarked populations. Migration of transpon ders away from the injection site has also been demonstrated and may c ompromise survival in some individuals. These risk factors could limit the use of implanted identification devices in long-lived or endanger ed species. Introduction of bacteria can be minimized by careful injec tion techniques and cleansing of instruments and skin with iodine or a lcohol. The choice of a suitable implantation site, such as midway dow n the back, from which transponders may migrate without impinging upon vital structures is also important. The believe that transponders, wh en used with care, provide a useful alternative to flipper bands in de mographic studies of penguins.