Researchers examine collision-related mortality among birds in Chicago. Collisions with human-built structures are a primary cause of mortality among nocturnally migrating birds. However, the factors underlying fatal bird collisions are unclear. Benjamin Van Doren and colleagues combined data collected between 2000 and 2020 pertaining to weather, bird migration intensity, and bird collisions in Chicago. The authors documented bird collisions with Chicago's McCormick Place Lakeside Center as well as the lighting output of each window bay in the building. Of the 11,567 fatal bird collisions documented between 2000 and 2020, 64.8% occurred in autumn. In both autumn and spring, nearly half of all documented collisions occurred on nights with large migration events, during which time McCormick Place was brightly lit. High fatality rates from collisions were also significantly correlated with high intensity of local migration, decreased moon illumination, and increased offshore winds. Given that few events were held at McCormick Place in 2020 due to the COVID-19 pandemic, the authors suggest, the building featured lower lighting and experienced fewer bird collisions in 2020 than in earlier years. The findings highlight the importance of human and environmental influences on bird collisions and suggest that minimizing building lighting at night could significantly reduce the collision rates of nocturnally migrating birds, according to the authors.
Article #21-01666: "Drivers of fatal bird collisions in an urban center," by Benjamin M. Van Doren et al.
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Proceedings of the National Academy of Sciences