marginally significantP = 0.06
The parents exhibited more-vigilant behaviour in the nest-box with an enlarged entrance (2.07 ± 0.41%) than in that with a control entrance (0.90 ± 0.41%), but this was marginally significant (mixed model, nest F 1,20.1 = 4.12, P = 0.06; playback F 1,21.3 = 0.28, P = 0.60; nest × playback F 1,20.9 = 2.93, P = 0.10; temperature F 1,36.0 = 2.05, P = 0.16; brood F 1,20.5 = 0.88, P = 0.36; Fig. 2b ).