Table 3.
Analysis of the effect of the genetic relatedness between helpers and nestlings on the provisioning rate of helpers, using a linear mixed effects model (number of observation periods = 404, number of individuals = 87, number of nests = 72). All biologically meaningful two-way interaction terms were also tested, and none were significant (p > 0.05). Significant p-values are shown in italic.
| random effects | variance | s.d. | |||
|---|---|---|---|---|---|
| bird identity | 4.926 | 2.219 | |||
| nest identity | 2.418 | 1.555 | |||
| residual | 7.284 | 2.699 | |||
| fixed effects | estimate | s.e. | χ2 | d.f. | p |
| (intercept) | −4.392 | 4.501 | — | — | — |
| year | — | — | 6.996 | 11 | 0.799 |
| date | 0.042 | 0.041 | 0.862 | 1 | 0.353 |
| time | −0 | 0.001 | 0.023 | 1 | 0.881 |
| nestling age | 0.258 | 0.059 | 21.249 | 1 | <0.001 |
| brood size | 0.584 | 0.169 | 13.469 | 1 | <0.001 |
| number of helpers | −1.226 | 0.293 | 18.398 | 1 | <0.001 |
| relatedness | 6.138 | 2.024 | 9.715 | 1 | 0.002 |