Table 3. GLM Predicted effects of supplementary feeding treatment and environmental variables on incubation duration in reed warblers.

Parameter	Estimate ± SE	F	P
Clutch size	1.01 ± 0.25	18.06	<0.0001
Rain	0.04 ± 0.01	10.91	0.0015
Invert avail.	0.01 ± 0.00	5.41	0.0229
Mean temperature	0.03 ± 0.05	1.12	0.2944
Treatment	1.71 ± 0.82	2.78	0.0997
Treatment × mean temp	-0.17 ± 0.07	6.47	0.0132