The widespread use of nest-boxes significantly improved our understanding of the ecology and behaviour of secondary cavity-nesting birds. Although former investigations showed that nest-box characteristics (e.g. physical dimensions, material) may determine where birds will roost or breed, biological consequences of the age of nest-boxes have been rarely investigated with field experiments. To test if age of cavities may influence roosting or breeding behaviour in cavity-nesting birds, we created a set-up of three experimental groups of wooden boxes with the same physical dimensions: old boxes that were occupied at least once for nesting during
years prior to this study, old boxes that were never accepted for breeding during years prior to this study, and new boxes. Half of the old boxes were relocated within the study plot and replaced by new ones. Box age did not have an impact on occupation rates during the winter period, and therefore did not seem to influence where the birds roosted. However, breeders occupied the old previously unoccupied boxes less frequently than the other boxes. Moreover, birds bred much earlier in new boxes than in the old boxes that were previously never exploited. We discuss when and how cavity age can influence roosting or breeding in nest-box exploiters. Our results
strongly suggest that maintenance procedures of plots where old boxes are replaced by new ones can influence how and where birds will breed.