Mean body mass of the 12 studied sea duck species and their respective six genera, according to a literature review.

Note: Species and genera are presented in increasing order of mass. n represents the total number of individuals included in the mean (see Methods for details on computations). Data are means ± SD. a: P.L. Flint, unpublished data; b: J.-F. Ouellet, unpublished data; c: F. Merkel, unpublished data.