Bird-of-prey decals on transparent noise barriers mitigate bird collisions, though not as much as dot-patterned stickers

Global annual bird mortality resulting from building window collisions is estimated to be billions. This study examined the impact of physical factors, including height, length, area, and the presence and type of mitigation stickers, on the number of bird collisions. The observational study was conducted from May to September 2021 in South Korea, focusing on 29 transparent noise barriers: 12 without mitigation stickers, 13 with bird-of-prey silhouettes, and 4 with dot stickers. Bird collisions were systematically recorded, and differences in collision numbers among different physical components of the barriers were analyzed using GLMs. We found a total of 297 collisions of 27 species. We found that the height of transparent noise barriers and the presence of mitigation stickers affected mortality. Our results highlight that attaching bird-of-prey decals reduces bird collisions, though not as much as dot-patterned stickers.