Table 1. Multinomial phylogenetically controlled generalized linear mixed models comparing the effect of ecoclimatic and life-history variables on the evolution of non-family-living, family-living, and cooperative breeding species; N = 2,968 bird species (excluding cooperative breeding species with non-kin helpers only).
Coefficients reflect the results of multinomial phylogenetic regression models with “cooperative families” as the reference category in the analyses and thus not shown per se. Significant factors are highlighted in bold. The principal component analyses (PCAs) resulting in PC1–8 are shown in S2 Table. The factor social system assessment specified whether it was assessed based on the time offspring remained with their parents beyond independence (using 50 days as a threshold to differentiate between non-family-living and family-living species; see [17]), breeding behavior, or social information. MCMC = Markov chain Monte Carlo.
| Family-living species (reference) versus non-family-living species: | Family-living species (reference) versus cooperative breeding species: | |||||||
|---|---|---|---|---|---|---|---|---|
| Factor | Mean estimated effect†* | 95% CI (lower; upper)* | f | p MCMC* | Mean estimated effect†* | 95% CI (lower; upper)* | f | p MCMC* |
| Intercept | 0.5 | –0.75; 1.88 | 0 | 0.46 | –0.76 | –1.83; 0.46 | 0 | 0.18 |
| Variable rainfall (PC1) | 0.42 | 0.2; 0.62 | 1 | 0.0011 | –0.02 | –0.31; 0.29 | 0 | 0.91 |
| Mean growing season duration (PC2) | –0.51 | –0.73; –0.3 | 1 | 0.0011 | 0.12 | –0.19; 0.44 | 0 | 0.47 |
| Within-year variance in productivity (PC3) | 0.22 | 0.05; 0.41 | 1 | 0.024 | –0.43 | –0.65; –0.13 | 1 | 0.0011 |
| Precipitation predictability (PC4) | –0.02 | –0.21; 0.19 | 0 | 0.83 | 0 | –0.27; 0.3 | 0 | 0.95 |
| Among-year variance in MGS's NPP (PC5) | –0.32 | –0.51; –0.12 | 1 | 0.0043 | 0.23 | –0.02; 0.48 | 0 | 0.063 |
| Residual geographic range (PC6) | 0.14 | –0.04; 0.32 | 0 | 0.13 | –0.09 | –0.32; 0.16 | 0 | 0.52 |
| Residual habitat openness (PC7) | 0.24 | 0.02; 0.45 | 1 | 0.034 | –0.16 | –0.47; 0.08 | 0 | 0.25 |
| Residual body size (PC8) | –0.92 | –1.32; –0.5 | 1 | 0.0011 | –0.07 | –0.52; 0.35 | 0 | 0.72 |
| Chick development modus (altricial versus precocial)‡ | –0.51 | –1.68; 0.68 | 0 | 0.43 | –0.61 | –1.91; 0.42 | 0 | 0.33 |
| Food specialization (generalist versus specialist) ‡ | –0.59 | –1.07; –0.22 | 1 | 0.0086 | 0.48 | –0.05; 1.07 | 0 | 0.1 |
| Sedentariness (sedentary versus migratory) ‡ | –0.94 | –1.45; –0.4 | 1 | 0.0011 | 0.34 | –0.46; 1.22 | 0 | 0.44 |
| Nest type (cavity versus open nesting) ‡ | –0.19 | –0.82; 0.44 | 0 | 0.51 | –0.36 | –1.09; 0.47 | 0 | 0.35 |
| Social system assessment—breeding behavior | –1.08 | –1.93; –0.19 | 1 | 0.013 | 4.2 | 3.46; 4.96 | 1 | 0.0011 |
| Social system assessment—social information | 0 | -0.37; 0.42 | 0 | 0.96 | –3.78 | –4.36; –3.09 | 1 | 0.0011 |
‡ Reference level is the first category in these lists
*Average over all 50 models
Abbreviations: f, frequency of trees for which MCMC p-values < 0.05 (N = 50 randomly selected phylogenetic trees); MGS, mean growing season, NPP, net primary productivity.