Table 2.

Individual-based analyses of plasticity quantifying the change in laying date between two consecutive years by female tree swallows in relationship to change in spring temperature and breeder density for (a) females observed as SY on the first year (n = 63), (b) females observed as ASY in both years (n = 311), (c) all females (n = 349; age was included as fixed effect)

Model	Variable	Estimate	SE	t-value	P-value
a) SY	Intercept	−8.159	1.246	6.55	<0.001
R² = 0.113	ΔTemperature	−3.742	1.256	2.98	0.004
	ΔDensity	−1.111	1.262	0.88	0.38
b) ASY	Intercept	−2.415	0.393	6.14	<0.001
R² = 0.099	ΔTemperature	−2.338	0.394	5.94	<0.001
	ΔDensity	−0.629	0.394	1.60	0.11
c) TOTAL	Intercept	−2.349	0.448	5.24	<0.001
R² = 0.158	Age	−5.683	1.056	5.38	<0.001
	ΔTemperature	−2.462	0.407	6.06	<0.001
	ΔDensity	−0.764	0.406	1.88	0.061

Variables in bold characters were kept in final models, and adjusted R² values are presented.