2021/06/01 by Michelle Vrettos, Chevonne Reynolds, Arjun Amar · 1 citation
Agricultural and Biological Sciences · Environmental Science · #Animal Behavior and Reproduction #Avian ecology and behavior #Wildlife Ecology and Conservation #GLARE #Plumage #Biology #Foraging #Ecology
paper · pdf · doi:10.1098/rsbl.2021.0116
openalex publication_date 2021/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Many falcons (Falco spp.) exhibit a distinct dark plumage patch below the eye, termed the malar stripe. This stripe is hypothesized to reduce the amount of solar glare reflected into the eyes while foraging, thereby increasing hunting efficiency in bright conditions. Here, we use a novel, global-scale correlative approach to test this ‘solar glare hypothesis' in peregrine falcons (Falco peregrinus), the most widespread falcon species, using web-sourced photographs from across the species' global range. We found that the size and prominence of the malar stripe were positively associated with average annual solar radiation, but not with other environmental variables, such as temperature and rainfall. Our results provide the first published evidence for the hypothesis that this plumage feature functions to reduce the amount of solar glare reflected into the falcon's eyes, thereby improving the ability to pinpoint and target agile prey in bright conditions.