The value of nestboxes in the conservation of Eurasian Rollers Coracias garrulus in southern Spain

The installation of nestboxes is a widely used conservation measure for enhancing habitat suitability for cavity-nesting birds wherever natural holes are scarce. However, nestboxes may attract birds to unsuitable breeding places or induce a non-random distribution of individuals in relation to their qualities. We investigated the factors influencing nestbox selection and the quality of breeding territories for the globally near-threatened Eurasian Roller in a semi-arid area of southeast of Spain over a 3-year period. Rollers preferentially used exposed nestboxes that were placed far from highly modified areas. However, breeding success was significantly lower in exposed nestboxes. Early breeders preferred nestboxes oriented to the northwest over any other orientation. Exposure had opposite effects on nestbox use and breeding success, suggesting that nestboxes installed in exposed sites could function as ecological traps for Rollers.