Standfirst: A year-long pilot study at an offshore wind farm in the Netherlands used thermal cameras and artificial intelligence to monitor birds and bats around a turbine. Researchers identified 22 possible bird collisions, while stressing that the results from one turbine cannot be applied to every offshore wind project.
Europe’s rapid expansion of offshore wind is creating a new scientific challenge: how to measure its effect on birds migrating across the North Sea, particularly at night and in poor visibility. A monitoring project at the Hollandse Kust Zuid wind farm has tested whether thermal imaging and artificial intelligence can provide evidence that is difficult to collect at sea.
The study was initiated by energy company Vattenfall in collaboration with Wildlife Imaging Systems and Wageningen University & Research. Sixteen thermal cameras were installed on one offshore turbine, covering all directions and operating continuously for almost a year.
What the offshore wind study found
The equipment monitored bird movements during both daylight and darkness, including periods of fog and rain. Across spring and autumn migration seasons, researchers recorded 22 possible bird collisions. Two were confirmed, while another was assessed as highly probable.
The findings are preliminary and were designed primarily to test the monitoring system under real offshore conditions. They do not establish that collisions are generally rare, nor do they provide a definitive estimate for the wider wind farm or the North Sea as a whole.
That limitation is important because offshore conditions make conventional surveys difficult. When a collision occurs at sea, remains may fall into the water and cannot easily be recovered. As a result, earlier estimates have often relied on models rather than direct observations.
Why night-time migration is difficult to monitor
Millions of songbirds cross the North Sea during seasonal migration, with many journeys taking place after dark. Larger birds are easier to observe in daylight, but small birds and bats can be difficult to detect when visibility is limited.
Thermal cameras can identify heat signatures in darkness, while artificial intelligence helps interpret flight paths and distinguish movement around turbine blades. The technology could eventually give researchers a more detailed picture of how birds respond to offshore structures.
How significant is the collision risk?
The Dutch pilot study forms part of a growing body of research, but the available evidence remains limited. A separate study by the German Offshore Wind Energy Association analysed more than four million bird movements over 18 months using radar and AI-supported cameras. It found that more than 99.8% of migratory birds avoided the turbines.
Vattenfall also monitored a turbine near Aberdeen, Scotland, for 19 months between June 2023 and December 2024. Researchers examined 2,007 bird flight paths and recorded no collisions in that sample.
These results suggest that avoidance behaviour may be widespread, but they do not remove the need for further research. Collision risk can vary according to species, weather, migration intensity, turbine design, lighting and the location of a wind farm.
- The Dutch project monitored one turbine rather than an entire offshore wind farm.
- The study covered both spring and autumn migration periods.
- Possible collisions were not all confirmed fatalities.
- Results from one site cannot automatically be applied across Europe.
Why the issue matters as offshore wind expands
Europe is a global leader in offshore wind, with more than 30 gigawatts of installed capacity across the continent. Ten countries—Belgium, Denmark, France, Germany, Iceland, Ireland, Luxembourg, the Netherlands, Norway and the United Kingdom—have also committed to developing 100GW of joint offshore wind projects in shared North Sea waters by 2050.
The expansion is intended to support the shift away from fossil fuels, but it must be balanced with biodiversity protection. Seabird populations already face pressures linked to climate change, habitat loss, changing food supplies and other human activities.
For Ireland, the research is relevant because the country is part of wider North Sea offshore wind cooperation and is developing its own offshore renewable-energy sector. Better monitoring methods could help inform environmental assessments for future projects, although the study does not prescribe how Irish developments should be designed or regulated.
Possible measures to protect birds
Researchers and conservationists are examining several ways to reduce risks before and after wind farms are built. Potential approaches include:
- placing turbines away from sensitive breeding and feeding habitats;
- avoiding major migration routes where reliable evidence identifies them;
- using radar and thermal cameras to monitor bird activity;
- improving turbine visibility in locations where evidence supports the approach;
- developing operational measures for periods of particularly high migration activity.
A land-based wind farm at Smøla in Norway tested painting one blade black on each of 68 turbines. The trial reported a reduction in recorded bird carcasses, although the results came from an onshore setting and cannot be assumed to apply offshore.
Greater visibility could also have drawbacks. Some researchers and critics have raised concerns that birds may take longer routes around turbines, increasing the energy required for migration and potentially affecting journeys to breeding sites.
What happens next?
The immediate value of the North Sea project is methodological. It shows how continuous thermal imaging and AI analysis can gather direct observations where traditional searches are impractical. More turbines, sites and migration seasons will need to be studied before scientists can produce robust regional estimates.
As offshore wind projects expand, environmental planning will increasingly depend on site-specific evidence. The key question is not simply whether birds approach turbines, but which species are affected, under what conditions and which mitigation measures work without undermining the reliability of renewable-energy generation.
Conclusion
The new offshore wind study provides useful evidence, but not a final answer about bird mortality across the North Sea. Thermal cameras and artificial intelligence could improve future monitoring, allowing developers and regulators to identify risks more accurately while Europe expands renewable energy. The central takeaway is that offshore wind development and bird conservation must advance together, supported by long-term, site-specific research.
