LAUSR

ABSTRACT Seabirds are widely considered sentinels of their coastal ecosystems. However, biological associations between specific marine and terrestrial factors and seabird health are less well understood. Here, we investigate the associations between habitat‐scale processes and variability in body condition of breeding little penguins Eudyptula minor, across 15 populations in Lutruwita/Tasmania, Australia. Sites represent a range of nesting habitats, oceanographic conditions and localised anthropogenic disturbance, providing an unparalleled opportunity to assess the impact of multiple processes shaping health. We show significant regional differences in body condition, with eastern populations consistently in better body condition than northern. Using Bayesian multilevel models, we found marine productivity to have the strongest relationship (coef. 0.52, 95% CI [0.13, 0.91]). Body condition was also negatively related to habitat loss, expressed as total road length around the colony, and ectoparasite load, with parasitism having a greater negative association in females. By assessing health across a spatially robust number of populations, rarely performed in seabirds, we reveal marine, terrestrial and sex relationships, indicating potentially important processes shaping health that would otherwise be difficult to discern.