Off the coast of Zhejiang, China, seabirds alter their flight behavior in the immediate vicinity of an offshore wind farm. To investigate this, researchers tracked three adult bridled terns near their breeding colony in 2023 and analyzed high-resolution satellite data. The study, published on July 29, 2026, reveals more pronounced course changes and lower flight altitudes when the birds fly directly toward the turbines. Crucially, the orientation of the flight path relative to the structures was more significant than the absolute distance. While the birds may incur additional energy costs, the small sample size does not demonstrate any impact on the population as a whole.
Seabirds alter flight paths and altitudes near wind turbines
The birds studied were nesting on Youbeng Island in Xiangshan County, the site of the Xiangshan No. 1 wind farm, which comprises 41 turbines with a total capacity of 254.2 megawatts. The nearest turbine is located approximately 800 meters from the center of the breeding colony. Tracking devices recorded flight movements during the breeding season between July and September 2023.
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Seabirds reacted particularly strongly when directly approaching an obstacle. Course alterations increased in a statistically measurable way as the birds oriented themselves more directly toward the facility. At the same time, flight altitude decreased. For every degree of reduction in angular deviation, the mean course alteration increased by 0.38 degrees. Additionally, altitude decreased by a calculated 0.41 meters.
Distance alone does not explain the reaction
However, the offshore wind farm did not automatically trigger the same reactions during every approach. Researchers found no simple linear relationship between distance and all the flight parameters studied. Instead, the decisive factor was whether the flight path was actually heading toward an obstacle. The study thus distinguishes between spatial proximity and a concrete encounter situation.
Recent studies from Europe also reveal significant differences between individual bird species. Researchers tracked 58 lesser black-backed gulls using GPS transmitters at Neeltje Jans in the Netherlands. The birds clearly avoided the local wind farm, and this effect could not be explained by fishing activity alone. Furthermore, males flew through the wind farm more frequently than females.
Impacts vary by bird species
A Norwegian model illustrates the difficulty of making sweeping generalizations about offshore wind power and seabirds. For common guillemots, researchers predicted significant displacement from key habitats in hypothetical wind farm scenarios. In contrast, the modeled collision risk for black-legged kittiwakes remained very low. Flight altitude, foraging habits, and species-specific behavior are thus key determinants of potential impacts.
The Chinese study therefore primarily provides indications of small-scale behavioral adjustments. However, a sample of three birds is insufficient to determine impacts on the population as a whole. Moreover, the study did not record actual collision numbers or measure additional energy expenditure. Consequently, larger-scale studies are needed to clarify whether repeated detours affect reproduction or survival rates.
Flight corridors could become increasingly important in planning
Spatial planning may play a greater role in the development of future offshore wind farms. Consequently, flight corridors between breeding grounds and foraging areas should be taken into account alongside standard minimum separation distances. However, studies conducted in the North Sea have so far failed to yield a consistent picture regarding the effectiveness of wider corridors between turbines.
Current findings therefore argue in favor of species-specific assessments rather than blanket assumptions. Wind turbines can cause certain species to avoid an area or alter their flight paths, whereas others show a much weaker response. Ultimately, the specific site, flight path, flight altitude, and behavior of the species in question remain the decisive factors.
Author: Blackout News
Sources: Wiley (29.07.26) – Research Institute Nature and Forest (Stand: 13.08.26) – Journal of Animal Ecology (08.06.26)