Table 3.

The opportunity for sexual selection varies for gray catbirds breeding in two different ecological contexts. Standardized variances in apparent (number of social young produced, var (T_A)) and realized reproductive success (number of offspring sired based on molecular paternity, var (T)) were calculated and weighted according to Webster et al. (1995). Components of variance were partitioned to determine the contribution of within-pair reproductive success (W), extra-pair reproductive success (E), and the covariance between the two (W, E) across two breeding seasons.

	Suburban matrix (N= 69)		Suburban park (N= 146)
	Standardized value1	Total percentage	Standardized value1	Total percentage
var (TA)	0.872		1.27
var (T)	0.826	100.0	1.15	100.0
var (W)	0.750	90.8	0.991	85.7
var (E)	0.059	7.1	0.163	14.2
cov (W, E)	0.017	2.1	0.001	0.10

¹Variance/mean².