Congratulations to Holly Hennin who’s third PhD thesis chapter entitled “Energetic physiology mediates individual optimization of breeding phenology in a migratory Arctic seabird” has just been accepted in the journal American Naturalist. Outlined here in a recent Press Release, the paper uses over a decade of energetic physiology data to field-test a condition dependent optimization investment model and found that Arctic-breeding female eiders able to fatten at high rates while maintaining lower energetic demand have the earliest laying dates, a critical life-history trait in this species when breeding in short-season Arctic environments. Well done to Holly and her co-authors on a great paper.