Table 2.

Multimodel inference on the effects of climate, migration, and habitat on male singing behavior in the Mimidae. We present the relative variable importance ^a and, in parentheses, the model-averaged coefficients, ${\stackrel{\sim }{\overline{\beta }}}_j$ , for each independent variable. The proportion of variability in the data that is accounted for by each model (R²) is presented at the bottom. Interpretation of the coefficients in this table is facilitated by inspection of bivariate correlations in Table 3.

Independent variable	Song parameter
	Mimicry Syndrome	Short-term Diversity	Song Complexity
Migration b	0.981 (−0.088, 0.649)	0.746 (−0.256, −0.514)	0.074 (0.006, 0.014)
Habitat c	0.178 (0.013)	0.214 (−0.020)	0.423 (0.129)
CV in precipitation	0.189 (−0.019)	0.230 (−0.032)	0.399 (0.164)
Predictability of temperature	0.416 (−1.217)	0.207 (0.144)	0.334 (0.959)
Climatic Composite d	0.229 (−0.020)	0.240 (0.020)	0.403 (0.054)
R2	0.531	0.191	0.102

^aRelative importance is computed as the sum of the Akaike weights of the set of models in which the variable appears. This parameter reflects how important is the variable in predicting the song parameter (0=no predictive value, 1=high predictive value).

^bReference category is “obligate migrant”. The two coefficients presented in parentheses refer to non-migratory and facultative migrant respectively.

^cReference category is ‘forest’.

^dHigher scores imply wider temperature ranges, more variable temperature, less predictable precipitation and a narrower range of precipitation (see text for details)