A citizen science network for monitoring nocturnal migration in birds – VOLDENUIT

France lies at the crossroads of several major migration routes for Eurasian birds. Of the 320 species that regularly fly over the French territory, almost two-thirds move partially or even exclusively at night. This phenomenon of nocturnal migration remains relatively understudied to date, while at the same time many species are experiencing a marked decline. In addition to the factors affecting all migratory birds (e.g. habitat loss, deliberate destruction), species that have a nocturnal flight strategy are particularly likely to be impacted by more specific threats: collisions with vertical structures, especially in the context of the massive development of wind farms, or light pollution, which causes disorientation. To understand and limit these impacts, it is essential to accurately describe the spatial and temporal distribution of migrating birds. VOLDENUIT is a citizen science program designed to meet these objectives. It is based on a tested bioacoustic approach, which enables passive monitoring of nocturnal migration to be set up in any habitat using autonomous recorders. Over the 18 months of the project, our consortium will start a network of confirmed observers who will use a protocol tested over several years to launch a large-scale standardized data collection. At the same time, our team will continue to develop an artificial intelligence-based tool to automate the detection and identification of bird calls. In the medium term, the data collected will enable us to better understand the phenology of nocturnal migrants, their migration routes and how they are impacted by various anthropogenic disturbances. A strong emphasis will be placed on disseminating results, integrating feedback from the community and publishing for different audiences (scientists, general public, stakeholders) in order to maximize the impact of the knowledge acquired and rapidly propose applications in the field of conservation. In this sense, the development of free, public algorithms will enable the network to be extended to a wider, less specialized audience, and to ensure its long-term viability. In the long term, VOLDENUIT's results will also be used to explore issues of phenological migration shifts in relation to climate change.