Camera system sheds new light on bird collisions at sea

Research into bird collisions with offshore wind turbines has taken an important step forward. A yearlong pilot study at an offshore wind turbine has shown that thermal cameras and artificial intelligence can be used to directly observe potential collisions at sea. The technology proved effective under challenging conditions while also generating rare real-world data on bird movements around a wind turbine.

The study, initiated by the energy company Vattenfall, was carried out at the Hollandse Kust Zuid offshore wind farm in a collaboration between Wildlife Imaging Systems (WIS) and Wageningen University & Research (WUR). WIS developed a system using 16 thermal cameras installed on an offshore wind turbine, covering all angles and operating 24 hours a day. Combined with AI, the system detected and interpreted bird movements day and night, including in poor visibility such as fog or rain.

For their report, researchers from WUR analyzed the data to assess the system’s performance and identify opportunities for improvement. The trial provided insights into what the technology can do and how it could be further optimized for future use and a potential wider rollout.

“Safeguarding biodiversity is an important part of the energy transition,” says Karen Krijgsveld, a bird ecology researcher at Wageningen University & Research. “On land, we already know quite a lot about when and why birds collide with turbines, and which species are most at risk. As offshore wind energy continues to expand, we need to develop that same understanding at sea.”

From theoretical models to actual observations

Millions of songbirds cross the North Sea every year during spring and fall migration, mostly at night. The system allows researchers to detect these small birds and bats during hours of darkness, as well as larger birds during daylight hours. Because the technology reliably detected and analyzed bird movements offshore, researchers could also begin quantifying collision risk. Over almost a year of monitoring, covering both a spring and a fall migration season, 22 possible bird collisions were identified—two of which were confirmed and one considered highly probable.

“Until now, estimates of offshore bird collisions were mainly based on theoretical models,” explains Jesper Kyed Larsen, a bioscience expert at Vattenfall. “At sea, it is extremely difficult to verify fatalities because there are no remains to recover. This study demonstrates how we can get the empirical data needed to improve collision estimates and secure efficient mitigation measures.”

“The system developed by WIS is an important step forward in assessing the impacts of offshore wind turbines on birds and bats,” says Krijgsveld. “We now have a system that can measure bird and bat collisions offshore, and we can start to measure collisions and relate their occurrence to the local conditions.”

The study does not claim that collisions are rare or that these initial results from one turbine can be applied everywhere. The primary aim was to test the technology’s performance under real offshore conditions. That it worked well enough to generate initial observational data on collisions is an important additional outcome.

Building on these findings, the researchers are using the results and experience gained from the pilot in new research. This next phase will focus on collecting collision data across different conditions and locations, further fine-tuning the monitoring technology and improving understanding of when and under what circumstances bird collisions occur. This knowledge could ultimately support more effective mitigation strategies for offshore wind farms.

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Lisa Lock

BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021.

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Andrew Zinin

Master’s in physics with research experience. Long-time science news enthusiast. Plays key role in Science X’s editorial success.

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