Original ResearchPublished 5 March 2026Disease-driven variation in body reserves links social rank, flock size, and overwinter survival in European greenfinchesIndrikis A. Krams · Ronalds Krams · Sergejs Popovs · Colton B. Adams · Todd M. Freeberg · Tatjana KramaFrontiers in Bird Sciencedoi 10.3389/fbirs.2026.1779032