Table 1.
species | cortex thickness | outer melanin layer thickness | number of melanin granules | diameter of melanin granules | melanin density in outer layer (%) | melanin density in inner layer (%) |
---|---|---|---|---|---|---|
red-winged blackbird Agelaius phoeniceus | 111.52±3.37 | 188.96±5.25a | 1a | 188.96±5.25a | 70.24±7.53 | 44.73±2.50 |
scrub blackbird Dives warszewiczi | 164.51±6.16 | 367.97±44.62 | 2.28±0.33 | 161.55±11.01 | 61.03±14.22 | 20.65±3.45 |
bobolink Dolichonyx oryzivorus | 241.12±27.51 | 331.75±13.17 | 1a | 331.75±13.17 | 55.37±7.69 | 43.55±2.33 |
bronzed cowbird Molothrus aeneus | 82.38±2.37 | 223.61±7.28 | 1.89±0.07 | 118.38±3.24 | 76.91±4.54 | 35.65±4.20 |
brown-headed cowbird Molothrus ater | 121.29±1.98 | 265.92±8.43 | 1.17±0.03 | 227.93±6.90 | 63.33±1.59 | 20.66±1.95 |
shiny cowbird Molothrus bonariensis | 84.22±2.56 | 281.50±10.05 | 1.33±0.04 | 211.12±11.74 | 78.99±4.98 | 28.27±2.05 |
screaming cowbird Molothrus rufoaxillaris | 117.06±3.97 | 229.39±6.32a | 1a | 229.39±6.32a | 68.31±3.62 | 40.70±2.64 |
great-tailed grackle Quiscalus major | 123.47±2.28 | 438.05±25.33 | 2.93±0.20 | 139.34±8.22 | 55.37±7.96 | 25.66±1.54 |
boat-tailed grackle Quiscalus mexicanus | 111.94±5.48 | 391.05±20.01 | 2.90±0.12 | 134.84±10.02 | 48.52±5.13 | 17.82±3.98 |
giant cowbird Scaphidura oryzivora | 61.14±1.21 | 274.18±8.94 | 1.08±0.01 | 253.70±4.03 | 80.45±9.58 | 34.21±2.71 |
western meaddowlark Sturnella neglecta | 110.18±7.89 | 230.34±6.33 | 1a | 230.34±6.33 | 70.33±6.53 | 42.33±2.20 |
Clear outer melanin layers were not present in these species, and we therefore measured the diameter of the single outermost melanin granule at six points on the barbule.