Similar Breeding Success of Bearded Vultures in Disturbed and Undisturbed Areas Shows Evidence of Adaptation Capabilities

Abstract

Human activities are usually considered as disturbing factors impeding the breeding success of wild animals. Protected areas can then be set up to restrict such activities aiming to improve wildlife’s breeding success and conservation. To test for the efficiency of these measures, we compared the breeding success of bearded vultures (Gypaetus barbatus) in the western French Pyrenees from autumn 2011 to spring 2017, where eyries are located either within or outside restricted areas, where potentially disturbing activities are restricted (e.g., helicopter flights, forestry works, hunting, paragliding). We monitored reproducing bearded vultures and checked the breeding success at different stages (laying, incubation, hatching, and survival at 2 months) of formed pairs. We then compared the success of each stage between eyries located in restricted and non-restricted areas, including weather data in our model. We found that the breeding success was similar in both types of areas, but that is was negatively impacted by precipitations, which may directly affect the ability of the egg or chick to withstand cold. We also focused on the potential disturbance of hunting parties on the behavior of bearded vultures and found no evidence that hunting was perceived as a threat by bearded vultures; they may in fact benefit from gut piles. Hence, our comparison of the breeding success between eyries located in restricted versus non-restricted areas shows no detrimental impact of human activities and calls for some studies to assess the effectiveness of restrictions in improving the breeding success of bearded vultures, as this species seems to show some degree of tolerance to human activities and may significantly suffer from harsh winter weather in this area.

Keywords

• bearded vulture
• breeding success
• gypaetus barbatus
• human disturbance
• hunting
• pyrenees
• species adaptation
• tolerance