Table 1.
Final linear mixed effect model (in bold) and model selection of variables and interactions explaining duckling feather corticosterone (fCORT)
| Dependent variable | Predictor variables | Estimate ± SE | t | P |
|---|---|---|---|---|
| Log(duckling fCORT) (pg/mm) | Sex (male) | − 4.44 ± 2.16 | − 2.06 | 0.04 |
| Maternal plasma CORT (ng/ml) | − 0.018 ± 0.009 | − 2.06 | 0.04 | |
| Clutch size | 0.22 ± 0.10 | 2.13 | 0.04 | |
| Hatch date | 0.06 ± 0.03 | 2.05 | 0.045 | |
| Growth (tarsus length incubation duration−1) | − 1.40 ± 1.24 | − 1.13 | 0.26 | |
| Sex (male) × growth | 4.00 ± 1.83 | 2.18 | 0.03 | |
| Maternal body condition | 0.26 ± 0.15 | 1.65 | 0.10 | |
| Sex × maternal RTL | − 0.28 ± 0.18 | − 1.61 | 0.11 | |
| Sex × maternal plasma CORT | − 0.014 ± 0.02 | − 0.89 | 0.38 | |
| Breeding experience (years) | − 0.023 ± 0.03 | − 0.84 | 0.41 | |
| Sex × maternal body condition | − 0.20 ± 0.28 | − 0.72 | 0.47 | |
| Sex × breeding experience | 0.044 ± 0.05 | 0.83 | 0.41 | |
| Time to maternal blood sample (s) | 0.00039 ± 0.0062 | 0.062 | 0.95 | |
| Standardized residual egg weight | 0.0073 ± 0.12 | 0.062 | 0.95 |
Given are the parameter estimates, standard errors (SE), t values and the P values; the model included maternal ID as a random effect (N = 181 ducklings and 58 females)