Abstract
Given the current climate of global warming and increasing energy consumption worldwide, wind power is an attractive resource as it is sustainable, with a low carbon footprint. However, wind farms can generate deaths caused by collisions with blades and towers. In order to limit this mortality, some wind farms use automated detection-reaction systems, that can detect birds at a distance and trigger a slowing down of the blades (≤ 5 m.s-1) if the bird(s) move(s) towards the wind turbines. Despite the installation of these systems, bird mortality persists, revealing a possible problem of visual perception of wind turbines by birds. Hence, the main objective of this thesis is to study how birds visually perceive wind turbines, in order to propose solutions for reducing the avian mortality. Through a number of experimental studies based on behaviour, this work first explores the sensitivity to achromatic contrasts of 32 bird species, from 12 phylogenetic orders, and highlights a sensitivity that may be insufficient to detect wind turbines under certain environmental conditions. Secondly, a study carried out with miniaturised wind turbines and birds from two species, Domestic Doves (Streptopelia roseogrisea) and Harris's Hawks (Parabuteo unicinctus), revealed an inability of Doves to discriminate rotating from static blades when the speed of rotation was < 5 m.s-1, with this speed threshold increasing when the contrast between the wind turbine and its background was low. Thirdly, a study on Pigeons (Columbia Livia) decision to cross a miniaturised rotor revealed an increased risk of crossing the area swept by the blades inversely proportional to the speed of rotation and frequency of the blades. This work led to the proposal of different patterns to be painted on wind turbines in order to optimise the detection of wind turbines, as well as the rotation of the blades, by birds. Finally, these results underline the importance of gaining a better understanding of how birds perceive movement, speed and danger, in order to reconcile human activities and structures with avian biodiversity.