Table 1. Study species, geographic locations and independent variables.
| Species | site | locations | bm (g) | hb | db | dc | mis |
| Euphagus cyanocephalus Brewer’s blackbird | CA | 4 | 64.0 | 3 | 4 | 93 | R |
| Euphagus cyanocephalus | MS | 3 | 65.2 | 3 | 4 | 93 | M |
| Euphagus carolinusRusty blackbird | MS | 5 | 61.6 | 2 | 6 | 31 | M |
| Quiscalus quisculaCommon grackle | MS | 10 | 95.2 | 3 | 5 | 85 | R/M |
| Molothrus ater aterBrown-headed blackbird | MS | 8 | 44.6 | 3 | 2 | 37 | R/M |
| Agelaius phoeniceusRed-winged blackbird | CA | 6 | 54.0 | 4 | 3 | 78 | R |
| Agelaius phoeniceus | MS | 10 | 63.2 | 4 | 3 | 78 | R/M |
| Agelaius tricolorTricolored blackbird | CA | 3 | 56.5 | 2 | 2 | 79 | R/M |
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.