Table 1. Correlations between body mass and reproductive characteristics for birds and mammals.

Correlations	Class	PGLS	N
Body mass vs. clutch/litter size	Birds	0	116
	Mammals	−***	353
Body mass vs. annual offspring number	Birds	+*	116
	Mammals	−***	203

Significance levels: *<0.05, **<0.01, ***<0.001. Correlations are given for double log-transformed data using phylogenetic generalised least square regression (PGLS). 0 no correlation, +significant positive correlation, - significant negative correlation. N sample size.