Table 1.
Model of the components of variance and covariance between nestling mass and survival from fledging to independence. The fixed effects were nestling sex, age at measurement (in days, fitted as a quadratic), the effect of the change in weighing protocol in 1992, brood size, the number of helpers in the group, the nestling's inbreeding coefficient, and whether or not it was the result of extra-pair paternity (EP, versus within-pair WP). The model was fitted in MCMCglmm with a Gaussian distribution for nestling mass and a threshold distribution for survival. The model estimates are based on posterior means, 95% credible intervals (CIs) are given in brackets, and p-values are based on pMCMC. Parameter estimates for survival terms are on the logit scale. The analysis is of 3808 nestlings in 1472 nests across 26 years (see electronic supplementary material, table S1 for details of sample sizes). Italics indicate pMCMC < 0.05.
| nestling mass |
survival from fledging to independence |
|||
|---|---|---|---|---|
| fixed effects | estimate (95% CI) | p | estimate (95% CI) | p |
| intercept | −3.35 (−6.00, −0.94) | 0.005 | 0.77 (0.15, 1.38) | 0.013 |
| 1992 (1992+, pre-1992) | ||||
| pre-1992 | 0.53 (0.33, 0.72) | <0.001 | ||
| nestling age | 2.06 (1.37, 2.81) | <0.001 | ||
| nestling age2 | −0.08 (−0.13, −0.03) | <0.001 | ||
| sex (female, male) | ||||
| male | 0.15 (0.11, 0.19) | <0.001 | 0.04 (−0.10, 0.16) | 0.574 |
| brood size | −0.05 (−0.09, −0.01) | 0.022 | −0.10 (−0.23, 0.04) | 0.138 |
| helpers (0, 1, 2+) | ||||
| 1 helper | 0.08 (0.01, 0.15) | 0.050 | 0.19 (−0.04, 0.42) | 0.109 |
| 2+ helpers | 0.15 (0.06, 0.24) | 0.002 | 0.27 (0.01, 0.53) | 0.037 |
| inbreeding coefficient | −3.23 (−5.98, −0.43) | 0.028 | −4.04 (−13.60, 5.48) | 0.423 |
| within-pair status (EP, WP) | ||||
| WP | 0.004 (−0.04, 0.05) | 0.855 | 0.09 (−0.05, 0.24) | 0.222 |
| random effects | variance–covariance–correlation matrices (95% CI) | |||
|---|---|---|---|---|
| mass | survival | |||
| nest ID | ||||
| mass | 0.23 (0.20, 0.25) | 0.05 (−0.04, 0.15) | ||
| survival | 0.03 (−0.03, 0.09) | 1.60 (1.12, 2.02) | ||
| hatch-date | ||||
| mass | 0.01 (0.002. 0.03) | 0.70 (0.23, 1.00) | ||
| survival | 0.07 (−0.01, 0.15) | 0.71 (0.17, 1.54) | ||
| cohort | ||||
| mass | 0.01 (1.06−5, 0.02) | 0.56 (0.03, 0.96) | ||
| survival | 0.02 (−0.001, 0.05) | 0.15 (0.04, 0.31) | ||
| additive genetic effect | ||||
| mass | 0.09 (0.06, 0.13) | −0.09 (−0.53, 0.28) | ||
| survival | −0.02 (−0.09,0.05) | 0.39 (0.07, 0.84) | ||
| residual variance | ||||
| mass | 0.19 (0.17, 0.21) | 0.11 (−0.01, 0.22) | ||
| survival | 0.05 (−0.003,0.10) | fixed to 1.00 | ||
| sample size | 3808 | |||