Which habitats are particularly suitable for Bearded Vultures? Sergio Vignali has investigated this question as part of a research project at the University of Bern. Besides a fundamental interest in this question, there is also a concrete conservation concern behind this work, which was done in close collaboration with our partners Stiftung Pro Bartgeier. Our very own Franziska Lörcher, the Vulture Conservation Foundation's (VCF) Science and Conservation Coordinator, and Daniel Hegglin, the VCF's Vice President, also significantly contributed to this study.
The potential risk of wind turbines to Bearded Vultures in the Alps
With the climate crisis posing a current global issue, renewable energy developments such as wind farms continue to develop extensively. This is also the case in the Alps.
The Bearded Vulture is currently a resident of the Alps following years of reintroduction efforts. The species is one of the largest soaring birds, using thermals to gain flight and venture into the mountains. Because it usually flies at relatively low altitudes, there is a significant risk that it will collide with rotor blades of wind turbines if they are planned in unsuitable locations.
The low reproductive rate of this species implies a particularly high survival rate. If new mortality risks are added, this can quickly cause the currently positive population trend to deteriorate again.
Assessing future distribution
Construction is usually prohibited within sensitivity zones around nesting sites to reduce the negative impacts of infrastructure projects on protected and endangered species.
This approach neglects the distribution dynamics of species and therefore does not provide adequate protection.
40% of the Alpine region suitable habitat for Bearded Vultures
Currently, 22 Bearded Vulture breeding pairs live in Switzerland. There are still many regions in the Alpine region where Bearded Vultures can establish themselves. Therefore, the extent to which Bearded Vultures will use these areas in the future must be estimated in advance before planning the location of wind energy plants.
For this purpose, predictive distribution models for the Bearded Vulture in Switzerland have been developed. They are based on a combination of random observations and GPS tracking data. The models show that 40 per cent of the Alpine region is a suitable habitat for the species.
Ibex and chamois prefer sunshine in the winter
The habitat models show that different environmental factors are important in winter and summer, and old and young animals also do not have identical habitat requirements.
In general, good occurrences of ibex and chamois seem to be important for the presence of Bearded Vultures. Limestone and granite are preferred over gneiss as substrate. Old birds particularly like places where there is a lot of sunshine in winter, and little rain is expected.
Maps for initial assessment of potential conflicts
Thanks to a better understanding of the habitat requirements of Bearded Vultures, maps can now be drawn up showing areas with particularly high conflict potential and which should not be used for wind turbines. Further in-depth site analyses are then only necessary in areas where significant conflicts are not expected from the outset.
Vignali, S., Lörcher, F., Hegglin, D., Arlettaz, R., & Braunisch, V. (2021). Modelling the habitat selection of the bearded vulture to predict areas of potential conflict with wind energy development in the Swiss Alps. Global Ecology And Conservation, 25, e01405. doi:10.1016/j.gecco.2020.e01405
* To get an even better picture the research group from the University of Berne is currently also developing a similar model for the Golden Eagle.