Diego García

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

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 affe...

Video-monitoring helps to optimize the rescue of second-hatched chicks in the endangered Bearded Vulture Gypaetus barbatus

Summary From 2000–2008 we used transmitting video cameras to document the breeding biology of the endangered Bearded Vulture in the Pyrenees (NE Spain), focusing the study on sibling aggression. Our goals were to study the feasibility of rescuing second-hatched chicks for conservation purposes in this species that shows obligate brood reduction. The age at which the second chick died varied between 4 and 9 days (n 55). Prey items delivered per hour were not related to the survival time of the second chick or the aggressiveness of the first-hatched chick towards their sibling. Although sibling aggression generally began on day 1 after hatching, in two nests supplemented with food, aggression was delayed until the second and third day after hatching and the second chick survived for nine days. Our results on the death of the second chick and the test involving the rescuing of a second-hatched chick aged five days, suggest that the recommended age for intervention should be between 3 and 6 days, with 4–5 days probably being the optimal age for the rescue.

Intraspecific nest usurpation in the bearded vulture Gypaetus barbatus in Catalonia (NE Spain)

Summary. 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.