The price tag

Abstract

Studies of animal populations often use tags to track the fate of individuals and assume that there is no adverse impact. Work on penguins shows that seemingly innocuous flipper bands affect survival and breeding success. See Letter p.203 For decades, the standard practice for studying penguins — well established as bellwethers of climate change — has been to tag the birds with flipper bands. It is a controversial technique, however, with conflicting reports on whether the tags themselves can alter the birds' behaviour. Now, the results of a ten-year study of free-ranging king penguins provide convincing evidence that banding is harmful. Banded birds had a markedly lower survival rate, with every major life-history trait affected, and they were more affected by climate variation than birds without bands. As well as raising doubts over marine ecosystem data based on banding, this work has implications for the ethics of animal tagging.