This is the peer reviewed version of the following article: Stier, A., Romestaing, C., Schull, Q., Lefol, E., Robin, J.-P., Roussel, D. and Bize, P. (2017), How to measure mitochondrial function in birds using red blood cells: a case study in the king penguin and perspectives in ecology and evolution. Methods Ecol Evol, 8: 1172–1182., which has been published in final form at DOI: 10.1111/2041-210X.12724. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.