Assessing exposure to wind turbines of a migratory raptor through its annual life cycle across continents

Unsustainable fossil fuel emissions have prompted a global shift towards renewable energy sources, such as wind. This has led to a strong expansion of wind power generation infrastructures, often conflicting with biodiversity conservation. Relatively large flying animals, such as birds and bats, have frequently been reported to collide with wind turbines, resulting in casualties that can depress population size and lead to local extinctions. Migratory species that move across continents through their year-round displacements may be especially at risk. We comprehensively assessed wind turbine exposure for a colonial migratory raptor of European conservation interest, the lesser kestrel Falco naumanni, based on the distribution and size of >1800 colonies and a large GPS-tracking dataset (>350 individuals) for three distinct biogeographical populations (from Iberian, Italian, and Balkan peninsulas). 26 % of the European population has at least one wind turbine within the foraging areas around colony sites, Italian colonies being most at risk. The main European network of protected areas, the Natura 2000 network, failed to mitigate the potential negative impact of wind turbines on breeding populations. GPS-tracking revealed that exposure was negligible in the African non-breeding areas (Sahel region), particularly high during migration, and lower during breeding for Iberian and Balkan individuals but not for Italian ones. Different countries should prioritize different measures to mitigate collision risk with wind power generation infrastructures. This case study can be leveraged by conservationists and renewable energy stakeholders to mitigate conflicts between biodiversity conservation and expected wind energy infrastructure development in the near future.This study was partly funded by the European Commission through the LIFE programme (LIFE17 NAT/IT/000586 LIFE FALKON) and by the Italian Ministry for University and Research (PRIN 2017 funding scheme, grant number 20178T2PSW to D. Rubolini). Lesser kestrel monitoring and tracking data in France were funded by the Plan national d'Actions pour le Faucon Crécerellette, by Office Français pour la Biodiversité (Migralion), and by OSU-OREME (SO ECOPOP). Most of the information on GPS-tagged birds in Spain originates from the MIGRA programme developed by SEO/BirdLife with the support of Fundación Iberdrola España and with the collaboration of GREFA, Córdoba Zoo, Alcalá de Henares Municipality, Global Nature Foundation and the European Commission (LIFE15 NAT/ES/000734 Steppe Farming), besides several Spanish environmental administrations and the collaboration of numerous field technicians and collaborators. The activity of GREFA was also supported by the Ministerio Para la Transición Ecológica y el Reto Demográfico. In Extremadura (Spain) tag deployment was conducted within the framework of LIFE project Gestión de ZEPA Urbanas en Extremadura (LIFE 15/NAT/ES/001016 ZEPAURBAN), while in Andalucía (Spain) tags were deployed within the framework of the “KESTRELS MOVE” project (CGL2016 79249 P, AEI/FEDER, UE). At the time of analyses and writing, L. López-Ricaurte and D. García-Silveira were supported by projects MERCURIO (rPID2020-115793GB, AEI/FEDER, UE) and SUMHAL (European Regional Development Fund LIFEWATCH-2019-09-CSIC-13, MICINN, POPE 2014-2020). Logistic and technical support in the field was provided by ICTS-RBD. I. Catry was funded by contract 2021.03224.CEECIND from FCT (Fundação para a Ciência e Tecnologia), J. Gameiro was supported by a post-doc scholarship (BIOPOLIS 2022-13), T. Catry was funded by contract 2021.00573.CEECIND from FCT (Fundação para a Ciência e Tecnologia). The authors acknowledge the support of NBFC to CNR, funded by the Italian Ministry of University and Research, PNRR, Missione 4 Componente 2, “Dalla ricerca all'impresa”, Investimento 1.4, Project CN00000033

Tracking data highlight the importance of human-induced mortality for large migratory birds at a flyway scale

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.publishedVersio