In Europe, the typical clutch of five–six eggs is laid between March and June, but in Japan three–five eggs are laid from May to July.[1] The eggs are white with very fine pinkish speckles mainly at the broad end,[2] measure 16 mm × 12 mm (0.63 in × 0.47 in) and weigh 1.2 g (0.042 oz) of which 6% is shell.[2] The eggs are incubated by the female alone for 13–17 days until the altricial downy chicks hatch; they are then fed by both parents, but brooded by the female alone, for a further 15–17 days to fledging.[5] Juveniles return to the nest for a few nights after fledging. About 20% of pairs, mainly in the south and west, raise a second brood.[2]