Different preferences for new versus old nestboxes by birds, rodents and social insects

The use of artificial nestboxes has improved the understanding of the ecology and behaviour of secondary cavity-nesting animals. Although earlier investigations have shown that nestbox characteristics can influence where animals roost or breed, the impact of ageing of nestboxes on occupation rates has rarely been investigated with experiments based on choice. In this study, the occupation rate of new and old wooden nestboxes set up side by side on the same tree (n = 140 pairs) was investigated in mixed coniferous-deciduous forest in Lithuania. Great tits Parus major and pied flycatchers Ficedula hypoleuca evidently preferred to breed in new nestboxes, while hazel dormice Muscardinus avellanarius and yellow-necked mice Apodemus flavicollis did not show any preference to a certain nestbox type and equally occupied old and new nestboxes. Saxon wasps Dolichovespula saxonica also occupied both nestbox types equally and a similar tendency was observed in European hornets Vespa crabro. By contrast, black garden ants Lasius niger showed a tendency to occupy old nestboxes. The results of the present study are important when considering the use of nestboxes in monitoring small hole-nesting birds and hazel dormice. The preference of birds for new nestboxes may influence long-term monitoring results when nestboxes become older and when old nestboxes are replaced with new ones. This important limitation has not been emphasised in review papers on the inadequacies of nestboxes in studies of hole-nesting birds. However, as ageing of nestboxes does not influence the occupation rates by hazel dormice, the use of nestboxes does not bias the results of long-term monitoring of this species