Table 1.

Allometric regression analyses of clutch in mass in birds for linear fits presented in figure 1. N is number of species, and CI is confidence interval. Italicized terms are significantly different than others with groups p < 0.05. See text.

	N	N orders	intercept	95% CI	slope	95% CI	r2	p
all
paternal	29	2	−0.2502	−0.5051–0.0046	0.8956	0.8064–0.9848	0.94	<0.00001
maternal	642	11	−0.1735	−0.2170–−0.1300	0.8816	0.8597–0.9034	0.91	<0.00001
bi-parental	583	23	0.1497	0.0868–0.2126	0.6641	0.6394–0.6889	0.83	<0.00001
precocial	270	6	0.0888	−0.0392–0.2169	0.8219	0.7760–0.8679	0.82	<0.00001
altricial	984	18	0.1036	0.0731–0.1341	0.6640	0.6497–0.6784	0.89	<0.00001
maternal
precocial	150	4	0.6298a	0.4365–0.8232	0.6672	0.6014–0.7330	0.73	<0.00001
altricial	492	7	0.1126	0.0710–0.1541	0.6539	0.6278–0.6800	0.83	<0.00001
bi-parental
precocial	91	6	0.2705	0.0705–0.4706	0.7038	0.6236–0.7841	0.77	<0.00001
altricial	492	18	0.1201	0.0596–0.1806	0.6598	0.6360–0.6835	0.86	<0.00001
paternal
precocial	29	2	−0.2502	−0.5051–0.0046	0.8956b	0.8064–0.9848	0.94	<0.00001
ratites	17	1	0.0813	−0.3630–0.5257	0.8128	0.6807–0.9450	0.92	<0.00001
Charadriiformes	12	1	0.3711	−0.4030–1.1451	0.5237	0.1220–0.9253	0.46	0.0157

^aDifferent from bi-parental precocial.

^bDifferent from maternal and bi-parental precocial.