Behavioral and functional responses of different bird clades to offshore windfarms in yellow sea, China.

Offshore windfarms (OWFs) constitute a rapidly expanding source of renewable energy that inevitably affects marine biodiversity, especially those built within critical areas for biodiversity conservation. To understand the potential effect of OWFs on bird communities, we systematically tracked bird communities and their behavior within OWFs near the Migratory Bird Sanctuaries along the Coast of the Yellow Sea in China from 2020 to 2022 using voyage investigations. The results indicated that bird diversity was greater within OWFs than in seawaters away from the OWFs. The composition of the bird community varied at different distance scales and the closer to the windfarm, the higher the number of birds from the Laridae and Anatidae. In addition, the flight heights of Laridae, Accipitridae, and Anatidae overlapped with the rotor-swept zones, and there were significant altitudinal variations in the OWFs and nearby waters. Based on 16 functional traits and the devised risk assessment function, we found that OWFs could have distinct impacts on different birds. Birds of the family Accipitridae, which have a larger body size, are likely to experience more stress from OWFs than other families. And, fish-eating birds, such as Laridae and Anatidae, have higher risk scores due to their closer proximity to the windfarm, medium body size and greater number of individuals. However, Passeriformes with smaller body size and fewer individuals have lower risk values. Our study revealed in detail the different strategies used by birds to cope with OWFs and provides a theoretical basis for rationalizing the conservation of bird diversity at these locations.