文摘
Collision with glass windows is a leading anthropogenic cause of direct mortality for avian species and much attention has been given to developing methods to reduce the incidence of bird collisions. Little empirical research exists, however, examining the mechanisms by which birds might be deterred from human structures. We tested the efficacy of ultraviolet (UV) lights for preventing window strikes in an urban environment by measuring their deterrence effect at bird feeders at eight residential sites. We used remote cameras to count feeder visits over one winter in response to rotating treatments comprising a pulsating UV light, a light-reflecting compact disc, an unlit UV light as a novel object, and a control with no object. Using generalized linear mixed models, we showed that feeder visit rates were influenced by wind speed, site, and site–treatment interactions. The unlit novel object treatment yielded a visitation rate significantly higher than the control (p = 0.01). The UV and passive reflecting treatments slightly increased visitation above the control (p = 0.06 and p = 0.378, respectively). This suggests that novel objects may serve as an attractant in a foraging context and that this effect is stronger than any deterrence effect of UV light. The site–treatment interaction indicated that each of the four treatments produced the highest visitation rate for at least one of the sites. Rather than offer a biological explanation for this interaction, we speculate that it resulted from a spurious effect of temporal and spatial variation in bird activity that interacted with our randomized block design. Although we found no evidence that UV lights would deter urban songbirds from anthropogenic structures, their potential to attract attention may reduce the likelihood that birds fail to see and then collide with windows. Keywords Passerines Ultraviolet light Human–wildlife conflict Behavior Conservation