Intraspecific Nest Usurpation in the Bearded VultureGypaetus barbatusin Catalonia (Ne Spain)

Abstract

Although interspecific competition for nests has been described in several raptor species, intraspecific interactions have rarely been reported. We describe three cases of intraspecific nest usurpation in the threatened bearded vulture Gypaetus barbatus in the Catalonian Pyrenees, where pairs were found nesting as close as 1.02 km apart. These observations could result from limited availability of suitable nesting habitat for this species, with birds being forced to compete for nest sites.