Table 1.

Content of the focal Great Tit nest when the Pied Flycatcher chose a nest box with the same, or a different, white marking as painted on the tit box

Study period	Number of eggs and/or nestlings in tit nest
	Female age	Nesting stagea	Same symbol box_		Different symbol box		t-test
			Mean ± SD	n	Mean ± SD	n	t	p
All		A	7.3 ± 1.7	24	8.0 ± 1.5	30	1.74	0.088
2017–2020	All	A	7.3 ± 1.7	21	8.1 ± 1.5	27	1.51	0.14
2016–2020	1st year	A	7.0 ± 1.8	9	7.7 ± 1.3	13	1.04	0.31
2016–2020	Older	A	8.0 ± 1.3	11	8.4 ± 1.6	14	0.73	0.48
2016–2020	All	Ab	7.8 ± 1.1	13	8.0 ± 1.4	22	0.44	0.67
2016–2020	All	B	8.0 ± 1.4	24	8.3 ± 1.4	30	0.89	0.38
2016–2020	All	Bc	8.1 ± 1.4	15	8.4 ± 1.7	14	0.54	0.54
2016–2020	All	Bd	7.8 ± 1.4	9	8.2 ± 1.1	16	0.81	0.43

The trials are separated according to study period, age of the female flycatcher, and nesting stage

^aA = The number of tit eggs and/or nestlings recorded on the day the female flycatcher started nest-building. B = The size of the completed tit clutch recorded during its incubation

^bOnly trials included where the flycatcher started nest-building before the tit eggs hatched

^cOnly trials where the respective symbols on the nest box and clutch sizes of the Great Tit and its nearest neighbour were consistent (see text)

^dThe remaining cases with symbols possibly causing confusion (see text)