Table 1.

Relationship between clutch size and nest base area in different studies and their 95% confidence intervals (CI)

Relationship	Species	F	df	P	Estimate (SE)	95% CI
A. Clutch size and base area in choice test (Löhrl 1973)	Parus major	28.61	1, 49	<0.0001	0.0088 (0.0016)	0.0056, 0.0120
B. Clutch size and base area when box is exchanged during laying (Löhrl 1980)	Parus major	6.48	1, 18	0.020	0.0264 (0.0104)	0.0045, 0.0483
C. Clutch size and change in base area when box is exchanged during laying (Löhrl 1980)	Parus major	6.48	1, 18	0.020	0.0132 (0.0052)	0.0033, 0.0241
D. Clutch size and base area in studies based on two or more nest box sizes	Parus major, Cyanistes caeruleus, Ficedula hypoleuca, Ficedula albicollis	6.50	1, 68	<0.0001	0.0036 (0.0014)	0.0009, 0.0063
E. Clutch size and base area in all studies of four secondary hole nesters	Parus major, Cyanistes caeruleus, Ficedula hypoleuca, Ficedula albicollis	3.37	1, 3371	0.067	−0.0211 (0.0115)	−0.044, 0.0014
F. Clutch size and base area in great tit	Parus major	24.31	1, 1434	<0.0001	0.0071 (0.0014)	0.0044, 0.0098
G. Clutch size and base area in blue tit	Cyanistes caeruleus	2.11	1, 382.2	0.15	−0.0038 (0.0026)	−0.0089, 0.0013
H. Clutch size and base area in pied flycatcher	Ficedula hypoleuca	0.65	1, 22.41	0.43	−0.0016 (0.0020)	−0.0055, 0.0023
I. Clutch size and base area in collared flycatcher	Ficedula albicollis	0.00	1, 32.29	0.99	0.000013 (0.0020)	−0.0039, 0.0039
J. Clutch size and base area in all open-nesting species	Open-nesters	9.90	1, 25	0.0037	0.0033 (0.0010)	0.0013, 0.0054
K. Clutch size and base area in all species	All species	12.51	1, 114	0.0006	0.0036 (0.0010)	0.0056, 0.0063