Study species, geographic locations and independent variables.

<p>bm: body mass; hb: habitat breadth, db: diet breadth, dc: diet change (high numbers indicate a large change in diet (high plasticity), small numbers a small change in diet (low plasticity)), mis: migratory strategy, CA: California, MS: Mississippi, R: resident, M: migratory, R/M: resident and migratory; explanation of the variables see text.