1. Wind energy production has expanded to meet climate change mitigation goals, but negative impacts of wind turbines have been reported on wildlife. Soaring birds are among the most affected groups with alarming fatality rates by collision with wind turbines and an escalating occupation of their migratory corridors. These birds have been described as changing their flight trajectories to avoid wind turbines, but this behaviour may lead to functional habitat loss, as suitable soaring areas in the proximity of wind turbines will likely be underused.
2. We modelled the displacement effect of wind turbines on black kites (Milvus migrans) tracked by GPS. We also evaluated the impact of this effect at the scale of the landscape by estimating how much suitable soaring area was lost to wind turbines.
3. We used state-of-art tracking devices to monitor the movements of 130 black kites in an area populated by wind turbines, at the migratory bottleneck of the Strait of Gibraltar. Landscape use by birds was mapped from GPS data using dynamic Brownian bridge movement models and generalized additive mixed modelling was used to estimate the effect of wind turbine proximity on bird use while accounting for orographic and thermal uplift availability.
4. We found that areas up to approximately 674 m away from the turbines were less used than expected given their uplift potential. Within that distance threshold, bird use decreased with the proximity to wind turbines. We estimated that the footprint of wind turbines affected 3-14% of the areas suitable for soaring in our study area.
5. We present evidence that the impacts of wind energy industry on soaring birds are greater than previously acknowledged. In addition to the commonly reported fatalities, the avoidance of turbines by soaring birds causes habitat losses in their movement corridors. Authorities should recognize this further impact of wind energy production and establish new regulations that protect soaring habitat. We also showed that soaring habitat for birds can be modelled at a fine scale using publicly available data. Such an approach can be used to plan low-impact placement of turbines in new wind energy developments.
Ana Teresa Marques, Carlos David Santos, Frank Hanssen, Antonio-Román Muñoz, Alejandro Onrubia, Martin Wikelski, Francisco Moreira, Jorge Manuel Palmeirim, João Paulo Silva
Centro de Ecologia, Evolução e Alterações Ambientais, Faculdade de Ciências, Universidade de Lisboa, EPortugal
Centro de Ecologia Aplicada “Professor Baeta Neves” (CEABN), InBio, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal
REN Biodiversity Chair, CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, Vairão, Portugal
Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany
Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Guamá, Belém, Brazil
Norwegian Institute for Nature Research, Trondheim, Norway
Biogeography, Diversity and Conservation Research Team, Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Spain
Fundación Migres (CIMA), Tarifa, Cádiz, Spain
Department of Biology, University of Konstanz, Germany
CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal
Journal of Animal Ecology. Published online (before print) 14 February 2019. doi:10.1111/1365-2656.12961 
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