Table 5.
Results from LMMs investigating how provisioning rates and dietary sources fed to nestlings varied across the three study sites.
| Response variable | |||||
|---|---|---|---|---|---|
| Explanatory variable | Estimate | Std. Error | df | t value | P value |
| (a) Visits per nestling (log) | |||||
| Intercept | 1.35 | 0.18 | 16.7 | 7.41 | <0.001 |
| Site | 0.25 | 0.08 | 14.9 | 3.05 | 0.008 |
| Time of day | −0.12 | 0.02 | 169.9 | −6.75 | <0.001 |
| (b) Visits per nest | |||||
| Intercept | 28.34 | 3.43 | 16.6 | 8.27 | <0.001 |
| Site | −3.29 | 1.52 | 15.0 | −2.16 | 0.047 |
| Time of day | −2.12 | 0.31 | 169.7 | −6.74 | <0.001 |
| (c) Mean volume of caterpillars (log) | |||||
| Intercept | 5.23 | 0.30 | 14.8 | 17.57 | <0.001 |
| Site | −0.33 | 0.14 | 14.9 | −2.43 | 0.028 |
| (d) Amount of caterpillars | |||||
| Intercept | 24.59 | 2.43 | 16.4 | 10.11 | <0.001 |
| Site | −6.51 | 1.08 | 15.0 | −6.01 | <0.001 |
| Time of day | −0.64 | 0.21 | 169.6 | −3.07 | 0.003 |
| (e) Amount of other arthropods (log) | |||||
| Intercept | 1.16 | 0.38 | 25.6 | 3.08 | <0.001 |
| Time of day | −0.20 | 0.08 | 46.7 | −2.63 | <0.011 |
| (f) Amount of unidentified items | |||||
| Intercept | 1.60 | 1.23 | 27.4 | 1.30 | 0.206 |
| Site | 1.97 | 0.47 | 13.8 | 4.23 | 0.001 |
| Time of day | −0.74 | 0.28 | 46.1 | −2.63 | 0.012 |
In all models, site, time of day and date were included as fixed effects, and dropped if not significant via backward selection (only significant variables are shown). Nest-box (brood) was included as random factor. We indicate in brackets whether the response variable was log-transformed.