Passive Integrated Transponders (PIT) on a small migratory passerine bird: absence of deleterious short and long-term effects

Abstrakti

Passive Integrated Transponder (PIT) tags have been widely used for ornithological research. However, only few studies have reported their impacts on individuals. We assessed the efficacy of subcutaneous PIT tag implantation in the mantel area of adult Pied Flycatchers (Ficedula hypoleuca). In addition, we investigated the short-term effects of the tags on body mass changes during the breeding period, and potential long-term effects by examining local return rate and apparent survival over winter. We focused on the impacts of carrying PIT tags. We compared individuals with subcutaneously implanted PIT tags and individuals that had PIT tags implanted but lost their tags within days of implantation. Overall retention of subcutaneously implanted PIT tags was ~77% in both breeding males and females. The tag retention was influenced by implanter experience. Body mass changes of PIT tag implanted individuals during the breeding period did not differ from those individuals that lost the tag soon after implantation. The apparent survival of PIT tag implanted males and females did not differ from individuals without tags in previous years. Our results suggest that the retention of PIT tags on breeding adults may not adversely affect their body condition prior to migration and their apparent survival.