Response of waterbird abundance and flight behavior to a coastal wind farm on the East Asian-Australasian Flyway

Coastal wetlands along migratory flyways are crucial in supporting staging or wintering waterbirds, yet they are often targeted for wind energy development. Potential conflicts are likely to be strong in densely populated East and Southeast Asia, where many bird species along the flyway are endangered, and wind energy projects are just flourishing. We investigated waterbird abundance and flight behavior at a coastal wind farm at the mid of the East Asian-Australasian Flyway. For shorebirds roosting in the aquacultural ponds, the abundance showed no significant change in the study area compared with the control area across all development stages of the wind farm. For egrets breeding in the mangroves, fewer Cattle Egrets Bubulcus ibis were observed in the year of wind farm construction and the first year of wind farm operation, then the number recovered afterwards. Since the operation of the wind farm, birds avoided crossing closely spaced (200 m) turbines while travelling through widely spaced (500 m) ones more frequently. Shorebirds, egrets, and landbirds flew lower when turbines were present, reducing the overlap of their flight height with the swept zone. Our study suggests that coastal wind farms are not necessarily a great threat to waterbirds. Yet environmentally sound planning and rigorous monitoring are crucial in minimizing potential impacts.