AOS 2018 Annual Conference

Bird window collisions (BWC) kill approximately 1.49 billion birds annually in North America and poses substantial concern for conserving bird populations across the continent. Recent research has greatly increased our understanding of factors influencing avian vulnerability to BWCs but the role of different avian life history strategies in influencing BWC risk has yet to be rigorously evaluated across multiple study sites. We used a standardized BWC monitoring protocol at 40 universities across North America to examine variation in collision vulnerability among birds with different life history strategies (e.g., foraging, nesting, and migratory strategies), and assess building-, vegetation-, and landscape-related characteristics influencing mortality of top species and guilds. Species collision vulnerability estimates accounted for sampling biases associated with numbers of buildings and days sampled, North American population abundance, and degree of species range overlap with sampling locations. Linear models and pairwise comparisons were used to assess relationships between collision vulnerability and guilds. Generalized linear mixed models were used to compare highly vulnerable species and guilds to principal components analysis of building, vegetation, and landscape metrics. 272 birds (67 species) were found as BWC victims and used in analyses. Species such as Black-throated Blue Warbler, Ruby-throated Hummingbird, Ovenbird, Yellow-bellied Sapsucker, and Gray-cheeked Thrush had disproportionately high collision vulnerability. Woodland-nesting, migratory, and insectivorous guilds comprised the majority of fatalities and therefore appear more vulnerable than species with alternative life history strategies. Our study linking life history strategies to BWC risk both increases mechanistic understanding and will help effectively mitigate BWC impacts continent-wide.