Are wind turbines a danger to birds?

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

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

Why it is to qualify

A real danger, hard to measure

Some wind farms pose a danger to bats and bird species, including sparrows and birds of prey. In France, a wind turbine would kill an average of seven birds a 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 loss is difficult to quantify accurately, especially because some of the corpses are recovered by natural predators.

According to a recent synthesis of knowledge, conducted by LPO, wind power can generate direct impacts, such as collision, or indirectly, associated with habitat loss as well as behavior change.

Bird mortality associated with offshore wind turbines is particularly difficult to quantify, as 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 places

“Not all wind projects are problematic. There is a very large heterogeneity with wind farms that kill very few birds and others that 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 for birds will have almost no effect on them. » Wind power poses a particular danger when projects are built on sites such as Natura 2000 sites, a European network for the conservation of biodiversity.

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

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

But the race to develop new parks is sometimes detrimental to these recommendations. “The glaring example is the development of parks in the Mediterranean, in Løvebugten, where we start impact studies of wildlife at the same time as the opening of the tender”, illustrates Frédéric Jiguet. The challenge is therefore not to ban wind power, the ornithologist believes, but better to plan and take into account the conservation of species upstream.

An assessment at the operators’ expense

According to a protocol validated by the Ministry of Ecological Transformation in 2018, operators must monitor the impact of their wind farms on the 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 areassorry Geoffrey Marx. The developer simply has to demonstrate that his project will not have a significant impact on the state of preservation of the site. »

The most problematic projects for biodiversity and endangered species are therefore often the subject of appeals from associations and collectives. This is the case, for example, in Oléron, where the offshore wind farm is controversial, especially 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 braked. Game detection and scare systems are also under investigation.

Researchers from the Norwegian Institute of Natural History have also suggested painting one of the wings of each wind turbine black after observing a 70% drop in bird mortality – especially among birds of prey – thanks to this process. The switch between black and white would allow the birds to better perceive the machines.

Thanks to ringtones, radars and various acoustic receivers, the preferred passageways, flow of individuals and flight behavior are analyzed in particular 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 main causes of bird mortality?

According to a recent study by the Royal Society for the Protection of Birds (RSPB), every sixth bird has disappeared in Europe since 1980, that is, almost 600 million breeding birds.

Similar observations have been made in North America, with a report from the American Bird Conservancy and the National Wildlife Research Center of Canada indicating a decline of about 3 billion birds in North America since the 1970s.

The main causes of bird species collapse include the use of pesticides and habitat destruction

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

In addition, nearly 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% longer distances, which increases fatigue and the risk of being killed by hunters.

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

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