Table 1.

Breeding season and maternal characteristics effects on tree swallow primary brood sex-ratio (proportion of males). Estimates were obtained from a mixed-effects logistic regression model with female and farm identities as random terms.

fixed effects	estimate	s.e.	t-value	p-value
hatching date	−0.002	0.002	1.26	0.21
clutch size	0.081	0.012	6.95	<0.001
maternal age (ASY 2006)	0.775	0.092	8.39	<0.001
season 2007	0.750	0.106	7.11	<0.001
season 2008	0.791	0.105	7.54	<0.001
maternal age × season 2007	−0.705	0.109	6.46	<0.001
maternal age × season 2008	−0.938	0.109	8.62	<0.001