Congratulations to Dr. Christine Madliger for having her recent paper “Employing individual measures of baseline glucocorticoids as population-level conservation biomarkers: considering within-individual variation in a breeding passerine” accepted to Conservation Physiology. The impetuous for Christine’s work was the observation that while the application of glucocorticoids (GCs) as conservation biomarkers has seen a huge increase, few studies have explicitly investigated whether baseline GC levels respond to disturbances consistently across individuals. Following individual female Tree swallows across multiple years, Christine’s work suggests that baseline GCs measured on a sub-set of individuals may not provide a representative indication of responses to environmental change at the population level and multiple within-individual measures may be necessary to determine the fitness correlates of GC levels. Fantastic work Christine.