Camera system sheds new light on bird collisions at sea
- dr. KL (Karen) Krijgsveld
- senior researcher bird ecology
Julian Hoffman
Research into bird collisions with offshore wind turbines has taken an important step forward. A year-long pilot 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 pilot, initiated by 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 sixteen thermal cameras that were installed on an offshore wind turbine, covering all angles and operating 24 hours a day. Combined with artificial intelligence, the system detected and interpreted bird movements during both day and night, and also in poor visibility such as fog or rain. Researchers from WUR analysed the data, helping to assess the system’s performance and identifying opportunities for further improvement. The trial provided important learnings on what the technology can do and how it can be further optimised for future use and potential wider roll out.
“Safeguarding biodiversity is an important part of the energy transition,” says Karen Krijgsveld, 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 autumn migration, mostly at night. The system allows detection of these small birds and also of bats during hours of darkness, as well as of larger birds during daylight hours. Because the technology proved capable of reliably detecting and analysing bird movements offshore, it was also possible to start quantifying collision risk. Over almost a year of monitoring, covering both a spring and an autumn migration season, 22 possible bird collisions were identified - two of which confirmed, and one considered highly probable.
“Until now, estimates of offshore bird collisions were mainly based on theoretical models,” explains Jesper Kyed Larsen, 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 Karen 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.”
Summary image showing various birds flying. A gull is flying by just in front of the camera; possibly taking off after having rested on the turbine; the other tracks show birds and insects at various distances.
Summary image showing three birds flying by through the field of view of the outward-looking cameras, as well as an insect that flies by vertically at close range.
The study does not claim that collisions are rare, nor that these first results from one turbine can simply be applied everywhere. The primary aim was to test the performance of the technology under real offshore conditions. The fact that it worked well enough to also generate first observational data on collisions is an important additional outcome.
Building on these findings, the researchers are now using the results and experience gained from this pilot study in new research. This next phase will focus on collecting collision data across different conditions and locations, on further finetuning the monitoring technology, and improving our understanding of when and under what circumstances bird collisions occur. This knowledge can ultimately support more effective mitigation strategies for offshore wind farms.
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