Are wind turbines a danger to birds?

Several presidential candidates, including Marine Le Pen, Nicolas Dupont-Aignan and Eric Zemmour, have come out against the development of wind farms.

During the “grand oral” organized by the National Federation of Hunters on March 22, Eric Zemmour declared in particular that wind turbines “disfigure our landscapes” and “constitute a threat” for the birds. It was not the first time that he invoked this argument, which should however be qualified.

Why it is to qualify

A real danger, difficult to measure

Some wind farms pose a danger to bats and bird species, including passerines and raptors. In France, a wind turbine would kill an average of seven birds per year, according to a mortality monitoring study published in 2017 by the League for the Protection of Birds (LPO). This would represent at least 56,000 birds, but the total losses are difficult to quantify precisely, in particular because part of the corpses are recovered by natural predators.

According to a recent synthesis of knowledge carried out by the LPO, wind power can generate direct impacts, such as collision, or indirect, linked to the loss of habitats as well as the modification of behaviour.

Bird mortality linked to offshore wind turbines is particularly difficult to quantify, since injured or dead birds that fall into the water are never found. “, emphasizes Frédéric Jiguet, ornithologist at the National Museum of Natural History.

Some problematic locations

“Not all wind projects are problematic. There is a very large heterogeneity with wind farms that kill very few birds and others, which are more problematicslice Geoffroy Marx, head of the renewable energy and biodiversity program at the LPO. A park located in a place that is not favorable to birds will have almost no impact on them. » Wind power poses a particular danger when projects are built in places like Natura 2000 areas, a European biodiversity conservation network.

If less than 5% of wind turbines are located on these sites, the mortality rate of endangered species is very high there. Half of the machines were built there even before the designation of Natura 2000 areas, according to Geoffroy Marx:

The excess mortality of birds is often linked to migratory phenomena, mainly at night when visibility is reduced (…) It is necessary at all costs to avoid areas where large raptors are present and migratory stopovers ».

However, the race to develop new parks is sometimes to the detriment of these recommendations. “The glaring example is the development of parks in the Mediterranean Sea, in the Gulf of Lion, where we start impact studies on wildlife at the same time as the opening of the call for tenders”, illustrates Frédéric Jiguet. The challenge is therefore not to ban wind power, according to the ornithologist, but to better plan and take into account the preservation of species upstream.

An assessment at the operators’ expense

According to a protocol validated by the Ministry of Ecological Transition in 2018, operators must monitor the impact of their wind farms on flying fauna, then assess them and take the necessary measures.

“In fact, there is no strict ban on the development of wind farms in certain areaslaments Geoffrey Marx. The developer just has to demonstrate that his project will not have a significant impact on the state of conservation of the site. »

The most problematic projects for biodiversity and endangered species are therefore often the subject of appeals by associations and collectives. This is for example the case in Oléron, where the marine wind farm is disputed, in particular because it is located in a Natura 2000 zone.

Technical solutions to reduce the impact

When birds are most likely to approach towers, machines can be stopped or slowed down. Wildlife detection and scaring systems are also under study.

Researchers from the Norwegian Institute of Nature Research have also suggested repainting one of the blades of each wind turbine black, after observing a 70% drop in bird mortality – especially among birds of prey – thanks to this process. The alternation between black and white would allow the birds to better perceive the machines.

Thanks to ringing, radars and various acoustic receivers, the preferential routes of passage, the flow of individuals and flight behavior are analyzed in particular in order to understand the threats to bird and bat populations. Other projects are underway to try to reduce the mortality of these animals.

What are the major causes of bird mortality?

According to a recent study by the Royal Society for the Protection of Birds (RSPB), one bird in six has disappeared in Europe since 1980, i.e. nearly 600 million breeding birds.

Similar observations are made in North America, where a report by the American Bird Conservancy and the National Wildlife Research Center of Canada indicates a decline of about 3 billion birds in North America since the 1970s.

Major causes of bird species collapse include pesticide use and habitat destruction

The causes of death are diverse. For example, domestic cats are a predator of garden birds. Based on several studies, the LPO made an extrapolation, calculating that cats would kill about 75 million birds per year. Apart from cats, collisions with power lines, vehicles and windows, the main causes of bird species collapse today are the use of pesticides in intensive agriculture, coupled with the destruction of habitats and soil artificialization.

In addition, almost 80% of migratory bird species will be threatened by climate change by 2050, according to a study published in the journal Nature Climate Change. Some migratory birds will have to travel 10% more distance, increasing fatigue and the risk of being killed by hunters.

“Tomorrow, climate change will be the main cause of the collapse of biodiversity”, concludes Geoffroy Marx. For the member of the LPO, it is therefore not a question “to accept anything with renewable energies”but it would be “criminal” to completely oppose it.

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