Light-induced Petrel Groundings in New Caledonia.

This study aims to identify the petrel species affected by artificial light pollution in New Caledonia, describe the spatial and temporal patterns of light-induced groundings, and infer the factors involved. The study took place across Grande Terre (New Caledonia's main island) from 2007 to 2009. A network of concerned citizens reported grounded seabirds. Live grounded birds were rescued and released when possible, or euthanized. Groundings were mapped at the scales of both Grande Terre and Nouméa, the main city. Negative binomial regression was used to analyze the effects of light intensity and proximity to shore on the number of groundings. Of the 523 grounded seabirds recorded between 2007 and 2009, 80.2% were wedge-tailed shearwaters (Ardenna pacifica), 14.2% were Gould's petrels (Pterodroma leucoptera), and 5.4% were Tahiti petrels (Pseudobulweria rostrata). Combining all three species, an estimated 64.9% of grounded individuals were fledglings. Groundings of Gould's petrels and wedge-tailed shearwaters peaked during their respective fledging seasons (April and May). The number of lights and the proximity to shore were identified as highly significant positive factors explaining the number of groundings. Groundings were particularly numerous at industrial sites and airports. Mortality upon discovery or within days after exceeded 47.8% in the wedge-tailed shearwater, 35% in Gould's petrel, and 23% in the Tahiti petrel. The results highlight the detrimental impact of outdoor artificial lighting on three petrel species breeding on Grande Terre, including the threatened Gould's petrel and the near-threatened Tahiti petrel. They provide evidence to support the urgent implementation of artificial light reduction policies at the periphery of Nouméa, around industrial sites, and near airports especially during the fledging periods.