Table 1.
Prediction of reproductive success (fledglings) and overall fitness (recruits) in four cohorts produced in years of contrasting conditions
| Species | Sex | F | N | adj R2 | Clutches | Longevity | Mates |
| 1978: Average rainfall (137 mm), low breeding density (2–3 broods) | |||||||
| Fledglings | |||||||
| G. fortis | F | 28.77 | 26 | 0.7144 | 0.0034 | 0.0042 | — |
| G. fortis | M | 39.21 | 36 | 0.7038 | 0.0011 | 0.0156 | — |
| G. scandens | F | 21.84 | 17 | 0.5928 | 0.0003 | — | — |
| G. scandens | M | 4.15* | 15 | 0.2418 | — | — | — |
| Recruits | |||||||
| G. fortis | F | 14.78 | 26 | 0.3811 | 0.0008 | — | — |
| G. fortis | M | 17.76 | 36 | 0.3431 | 0.0002 | — | — |
| G. scandens | F | 3.47* | 17 | 0.3316 | 0.0382 | 0.0227† | — |
| G. scandens | M | 5.25 | 15 | 0.2877 | — | 0.0393† | — |
| 1981: Low rainfall (73 mm), medium breeding density (1–2 broods) | |||||||
| Fledglings | |||||||
| G. fortis | F | 38.79 | 18 | 0.7080 | <0.0001 | — | — |
| G. fortis | M | 40.88 | 28 | 0.6112 | <0.0001 | — | — |
| G. scandens | F | — | — | — | — | — | — |
| G. scandens | M | 27.13 | 17 | 0.6439 | 0.0001 | — | — |
| Recruits | |||||||
| G. fortis | F | 15.78 | 18 | 0.4965 | 0.0011 | — | — |
| G. fortis | M | 39.32 | 28 | 0.6020 | <0.0001 | — | — |
| G. scandens | F | — | — | — | — | — | — |
| G. scandens | M | 16.91 | 17 | 0.5299 | 0.0009 | — | — |
| 1983: High rainfall (1,359 mm), high breeding density (<8 broods) | |||||||
| Fledglings | |||||||
| G. fortis | F | 114.40 | 155 | 0.6944 | <0.0001 | <0.0001 | 0.0251 |
| G. fortis | M | 158.05 | 94 | 0.7765 | <0.0001 | 0.0076 | — |
| G. scandens | F | 72.74 | 69 | 0.7705 | 0.0028 | 0.0002 | 0.0043 |
| G. scandens | M | 51.34 | 38 | 0.5878 | <0.0001 | — | — |
| Recruits | |||||||
| G. fortis | F | 232.99 | 155 | 0.6036 | <0.0001 | — | — |
| G. fortis | M | 52.82 | 94 | 0.5372 | 0.0001 | 0.0109 | — |
| G. scandens | F | 44.87 | 69 | 0.5762 | <0.0001 | — | 0.0039 |
| G. scandens | M | 23.19 | 38 | 0.3918 | <0.0001 | — | — |
| 1987: High rainfall (622 mm), medium breeding density (<7 broods) | |||||||
| Fledglings | |||||||
| G. fortis | F | 36.96 | 88 | 0.4651 | <0.0001 | 0.0347 | — |
| G. fortis | M | 22.80 | 82 | 0.4672 | <0.0001 | — | — |
| G. scandens | F | 22.57 | 13 | 0.6723 | 0.0006 | — | — |
| G. scandens | M | 34.71 | 17 | 0.6982 | <0.0001 | — | — |
| Recruits | |||||||
| G. fortis | F | 22.68 | 88 | 0.3479 | <0.0001 | — | 0.0072† |
| G. fortis | M | 29.84 | 82 | 0.2716 | <0.0001 | — | — |
| G. scandens | F | 3.59* | 13 | 0.2458 | — | — | — |
| G. scandens | M | 7.68 | 17 | 0.3386 | 0.0143 | — | — |
All F ratios are significant at P < 0.05 (most at P < 0.0001), except where indicated by an asterisk (*P > 0.05). Significance of partial regression coefficients of the predictor variables is given in the body of the table. All coefficients but three (indicated by †) are positive.