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Birds threatened by collisions with green energy infrastructure

With the transition to green energy becoming ever more pressing, countries are looking to expand their renewable energy infrastructure in order to meet future energy requirements. In Europe and northern Africa, this means the establishment of many more onshore wind turbines and electrical power cables to connect them to the grid. Such developments are essential in order to prevent runaway climate change, but may prove disastrous for populations of birds that risk collisions with this infrastructure.

New research led by the University of East Anglia (UEA) has used GPS location data from 65 bird tracking studies in order to identify the locations where birds fly more often at danger height and would therefore be at increased risk of colliding with wind turbines and power lines. They also assessed the locations of planned green energy infrastructure developments and identified potential collision hotspots where birds may be at increased risk of destruction.

The results, published today in the Journal of Applied Ecology, show that areas where birds are most vulnerable to collisions are particularly concentrated within important migration routes, along coastlines and near breeding locations. There was a high movement of individuals through the bottlenecks of the European-African Flyway, such as southern Iberia, as well as Sinai, the Gulf of Iskenderun and the Bosporus in Turkey. In addition, movement hotspots included the western Mediterranean coast of France and the Moroccan coast – around the Strait of Gibraltar – eastern Romania, and the Baltic coast of Germany.

The GPS location and altitude data that the researchers used related to 1,454 birds from 27 different species.  Dangerous heights for flying were considered to be 10–60 meters above ground for collision with power lines and 15-135 meters for wind turbines. The data showed that the risk of collision varied between species, with the large, soaring birds being most vulnerable. Species such as the Eurasian spoonbill, European eagle owl, whooper swan, Iberian imperial eagle and white stork were among those that fly consistently at heights where they risk collision.

The authors produced vulnerability maps identifying probable collision hotspots where birds would be more sensitive to onshore wind turbine or power line development. They say that the development of new wind turbines and transmission power lines should be minimized in these areas, and that if new energy infrastructure is developed there, it will need to take into account mitigation factors to reduce the risks to birds.

“We know from previous research that there are many more suitable locations to build wind turbines than we need in order to meet our clean energy targets up to 2050,” said Jethro Gauld, lead author and PhD researcher in UEA’s School of Environmental Sciences.

“If we can do a better job of assessing risks to biodiversity, such as collision risk for birds, into the planning process at an early stage we can help limit the impact of these developments on wildlife while still achieving our climate targets.”

“Our results will help achieve this and in doing so provide better outcomes for people and wildlife.”

Dr Aldina Franco, the project supervisor at UEA, said: “This collaborative study, including research from 51 researchers and 15 countries, is a great example of where working together can start to answer some of the big questions around the threats that African-Eurasian migrants face on their long annual journeys.”

According to Phil Atkinson, project supervisor from the British Trust for Ornithology, the use of high precision GPS devices allow experts to study birds’ movements in huge detail. “Birds do not respect country boundaries, and power lines and wind turbines impact migratory birds across their annual cycle, especially for large soaring birds such as raptors and storks.”

In the second phase of their study, the researchers overlaid their vulnerability maps derived from bird behavioral data on the locations of existing energy infrastructure to identify areas where birds are most exposed to current collision risks with wind turbines and power lines. 

“Our maps can also help target measures to reduce risks where previously built developments are already causing problems,” said Gauld. “They highlight the areas where existing energy infrastructure is already providing a source of collision risk for these birds. It is therefore a key conservation priority for additional measures to reduce collision risk are implemented in these vulnerability hotspots.”

“Such measures can include marking power lines to make them more visible, and implementing systems to allow shutdown of wind turbines during periods of high bird traffic.”

The transition to zero carbon energy will necessitate the construction of many new windfarms in the near future. For example, European onshore wind energy capacity is projected to grow nearly fourfold by 2050, and countries in the Middle East and North Africa, such as Morocco and Tunisia, also have their targets to increase the share of electricity supply from onshore wind. In addition to this, there will be a huge investment in new high voltage power lines, with an estimated fivefold increase in transmission capacity required between 2010 and 2050. 

Although these developments are essential, they will pose a challenge to wildlife, particularly birds and bats that fly at danger heights and are at risk of collision and electrocution. The researchers hope the study provides a method which other researchers and practitioners involved in environmental impact assessments for renewables can replicate as more data from tracking studies becomes available.

By Alison Bosman, Staff Writer

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