Nest use, interspecific relationships and competition for nests in the Bearded Vulture Gypaetus barbatus in the Pyrenees: influence on breeding success

Abstract

Nest use and interspecific relationships were studied in the Bearded Vulture for nest location in the eastern Pyrenees (NE Spain) and their influence on breeding success. A total of 40% (n = 70) of Bearded Vulture nests were usurped (expulsions) by other species, the Griffon Vulture being the species which occupied most nests (81%). Our observations suggest the active selection of nests by usurping species, which for the moment does not seem to influence the breeding success of the Bearded Vulture. The frequency of nest changes, the distance between nests and the productivities obtained do not differ significantly between territories with expulsions (60%) and those which still have all their nests available (40%). Nevertheless, expulsion may have a greater effect on those territories situated at high altitude or with few alternatives for resiting the nest. Since the displacement towards sectors with a greater human presence, or with locations more exposed to unfavourable environmental conditions, may affect breeding success, this may be important for the conservation of the species.