Bird deaths at French wind farms are relatively low, according to a recent study carried out by the League for the Protection of Birds (LPO).
However, mortality rates vary significantly between locations, with turbines situated near special conservation zones seeing twice as many deaths directly attributed to turbines, the LPO found.
The industry welcomes the finding that wind turbines do not have a large impact on biodiversity, said Guillaume Wendling, head of the environment commission at French wind energy association FEE.
"The study also shows that the industry has contributed a lot of scientific knowledge through its monitoring programmes," he added.
On the other hand, given that it was not scientifically validated, many of the conclusions are questionable, Wendling argued.
The study, the first in-depth analysis carried out on a national scale, looked at 197 monitoring reports covering 1,065 turbines at 142 projects.
This yielded 1,102 bodies found during nearly 38,000 inspections. Extrapolating the results, estimates of real mortality (taking into account the detection and decomposition rates of the bodies) vary from 0.3 to 18.3 birds killed per turbine per year, comparable with findings in the US and Canada.
In terms of species, migratory birds accounted for around 60% of the bodies found, the majority being passerines, which are mostly nocturnal migrants. However, breeding birds of prey were the most impacted in terms of their population size, while 75% of the 97 species found being officially protected in France.
The proximity of turbines to special protection zones (ZPS), aimed at protecting vulnerable birds, "is the main impact factor," noted Geoffrey Marx, head of LPO's renewable energies and biodiversity programme.
Twice as many bodies overall and nearly three quarters of those belonging to particularly vulnerable species listed in the European Bird Directive were found near turbines within one kilometre of a ZPS.
In response, the LPO is calling for a ban on turbines within a kilometre of a ZPS, a conclusion the industry contested. "It is not as simple as saying the increased deaths are due to the location of the turbine in or near a ZPS," Wendling argued.
It could also be because these are often old, smaller turbines, or because of more frequent monitoring, he said. Furthermore, "at a European level, wind turbines are seen as having a marginal impact on biodiversity, and are not regarded as incompatible with ZPS," Wendling added.
However, the industry is already working with the LPO on other recommendations, including developing a robust monitoring protocol to ensure a standardised evaluation of mortality.
This will allow "adaption on a case-by-case basis so as not to impose excessive monitoring on plant without environmental issues," Marx explained.
Wendling agreed that monitoring should be proportional, while stressing the need for the LPO and industry to work together.
Without this, he is worried the LPO's recommendations risk becoming a general directive imposed on the sector. "The data is interesting. The conclusions should now be debated and discussed," he said.