Behavioral responses to offshore windfarms during migration of a declining shorebird species revealed by GPS-telemetry

• Published in: Journal of Environmental Management
• Main Authors: Schwemmer, Philipp, Mercker, Moritz, Haecker, Karena, Kruckenberg, Helmut, Kämpfer, Steffen, Bocher, Pierrick, Fort, Jérôme, Jiguet, Frédéric, Franks, Samantha, Elts, Jaanus, Marja, Riho, Piha, Markus, Rousseau, Pierre, Pederson, Rebecca, Düttmann, Heinz, Fartmann, Thomas, Garthe, Stefan
• Other Authors: Christian-Albrechts-Universität zu Kiel (CAU), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie et des Sciences de la COnservation (CESCO), Muséum national d'Histoire naturelle (MNHN)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ligue pour la Protection des Oiseaux (LPO), Universität Osnabrück - Osnabrück University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Marine spatial planning; Eurasian curlew (Numenius arquata); Flight altitude; Collision risk; Biologging; Avoidance behavior; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; Eurasian Curlew; Numenius arquata
• Online Access: https://hal.science/hal-04101472; https://hal.science/hal-04101472/document; https://hal.science/hal-04101472/file/1-s2.0-S0301479723009192-main.pdf; https://doi.org/10.1016/j.jenvman.2023.118131

International audience EU member countries and the UK are currently installing numerous offshore windfarms (OWFs) in the Baltic and North Seas to achieve decarbonization of their energy systems. OWFs may have adverse effects on birds; however, estimates of collision risks and barrier effects for migratory species are notably lacking, but are essential to inform marine spatial planning. We therefore compiled an international dataset consisting of 259 migration tracks for 143 Global Positioning System-tagged Eurasian curlews (Numenius arquata arquata) from seven European countries recorded over 6 years, to assess individual response behaviors when approaching OWFs in the North and Baltic Seas at two different spatial scales (i.e. up to 3.5 km and up to 30 km distance). Generalized additive mixed models revealed a significant small-scale increase in flight altitudes, which was strongest at 0–500 m from the OWF and which was more pronounced during autumn than during spring, due to higher proportions of time spent migrating at rotor level. Furthermore, four different small-scale integrated step selection models consistently detected horizontal avoidance responses in about 70% of approaching curlews, which was strongest at approximately 450 m from the OWFs. No distinct, large-scale avoidance effects were observed on the horizontal plane, although they could possibly have been confounded by changes in flight altitudes close to land. Overall, 28.8% of the flight tracks crossed OWFs at least once during migration. Flight altitudes within the OWFs overlapped with the rotor level to a high degree in autumn (50%) but to a significantly lesser extent in spring (18.5%). Approximately 15.8% and 5.8% of the entire curlew population were estimated to be at increased risk during autumn and spring migration, respectively. Our data clearly show strong small-scale avoidance responses, which are likely to reduce collision risk, but simultaneously highlight the substantial barrier effect of OWFs for migrating species. Although ...