Table S4.

Results for all signal-of-quality models: fixed effects

Model no.	Log Lik	Fixed effects	df	Wald statistic	P value	N species	N study	N observations	Notes
9	107.5	Intercept	1, 16.8	4.23	0.056	18	33	140	Full dataset
		Brood size	1, 18.8	1.06	0.32
10	107.0	Intercept	1, 13.9	2.67	0.12
		Brood size	1, 17.0	0.18	0.68
		Predictability	1, 11.3	0.69	0.42
		Quality	2, 133.0	7.61	0.00075
		Predictability * Quality	2, 133.0	3.74	0.026
11	84.0	Intercept	1, 12.4	2.24	0.16	16	30	115	Excluding 2 species missing data on adult mortality or the broods possible each breeding season
		Brood size	1, 14.7	0.88	0.36
		No. of future broods possible	1, 10.1	0.11	0.75
12	86.3	Intercept	1, 10.5	1.83	0.20
		Brood size	1, 12.1	0.38	0.55
		No. of future broods possible	1, 11.4	0.21	0.66
		Predictability	1, 9.6	0.03	0.88
		Quality	2, 107.0	10.18	0.00009
13	75.0	Intercept	1, 5.2	0.78	0.42	10	20	80	Excluding 8 species missing data on adult mortality, the broods possible each breeding season, or mating system
		Brood size	1, 5.7	0.00	0.97
		No. of future broods possible	1, 4.3	0.24	0.65
		Full vs. half siblings likelihood	1, 4.3	0.46	0.53
14	73.6	Intercept	1, 4.0	0.99	0.38
		Brood size	1, 4.3	0.10	0.77
		No. of future broods possible	1, 3.7	0.13	0.74
		Full vs. half siblings likelihood	1, 3.4	0.06	0.82
		Predictability	1, 3.6	0.16	0.72
		Quality	1, 73.0	4.83	0.011

Mean results of 500 ASReml linear mixed models. Models controlled for phylogeny, repeated measures on studies, and species, and were weighted by study sample size (the number of broods used to calculate the original test statistic). Fixed effects in bold are significant at the P < 0.05 level and in italics at the P < 0.10 level. Models are grouped by the dataset used for analysis, and the notes column describes the loss in sample size due to missing life history data. Models did not converge when promiscuity was included as a fixed effect.