TABLE 1.

Summary of the PGLS models for examining the effects of (A) clutch size, (B) nest attachment, (C) nest site and (D) nest structure on C number among the studied species

	Coefficient	SE	t	p	Lambda
(A) Clutch size					0.494
Intercept	4.156	0.052	80.684	<0.001
Clutch size	0.017	0.002	7.971	<0.001
(B) Nest attachment					0.461
Intercept	4.144	0.049	85.231	<0.001
Lateral/horizontal versus basal	0.052	0.019	2.719	0.007
Pensile versus basal	0.111	0.024	4.551	<0.001
Clutch size	0.017	0.002	8.197	<0.001
(C) Nest site					0.444
Intercept	4.099	0.047	86.479	<0.001
Tree versus others	0.050	0.011	4.697	<0.001
Non‐tree vegetation versus others	0.081	0.010	7.759	<0.001
Clutch size	0.017	0.002	8.098	<0.001
(D) Nest structure					0.456
Intercept	4.099	0.046	89.696	<0.001
Cavity versus scrape/platform	0.066	0.013	5.159	<0.001
Cup versus scrape/platform	0.070	0.011	6.619	<0.001
Dome versus scrape/platform	0.136	0.014	9.572	<0.001
Clutch size	0.016	0.002	7.586	<0.001

In the models for nest characters, clutch size was included as an independent variable to account for its confounding effect.