Data from: Is telomere length a molecular marker of individual quality? insights from a long-lived bird

1. In wild vertebrates, some individuals survive and reproduce better than others and this has led to the concept of individual quality. Despite its importance when studying ecological processes and life-history trade-offs, measuring individual quality is complex because individuals must be followed during a large part of their life. 2. Recently, telomere biology has been successfully brought into ecology and telomere length has been suggested to be a promising molecular tool to evaluate individual quality in wild vertebrates (‘the telomere – individual quality hypothesis’). 3. In this study, we tested this hypothesis in a long-lived species, the Black-browed albatross (Thalassarche melanophrys) by simultaneously measuring telomere length and several potential complementary phenotypic proxies of individual quality in a single year. In addition, we followed the return rate and the reproductive performance of these same albatrosses for a decade. 4. We found that long telomeres were associated with several markers of high individual quality (foraging behaviour, body size, and stress hormone levels). Furthermore, we found that a single measure of telomere length could predict future offspring productivity, for at least several years following telomere measurement (better productivity being associated with longer telomeres). 5. Altogether, these results support the ‘telomere – individual quality hypothesis’ and suggest that telomere length can be useful to estimate individual quality in long-lived seabirds