Betleja, Jacek, Łukasz Jankowiak, Tim H. Sparks, and Piotr Tryjanowski. “Birds Crossing over Roads: Species, Flight Heights and Infrastructure Use”. European Journal of Ecology 6, no. 2 (December 31, 2020). Accessed May 4, 2024. https://journals.ku.edu/EuroJEcol/article/view/14788.