Bird populations across North American have declined over the past 50 years, with a cumulative loss of billions of breeding birds across species and habitat types. Aerial insectivorous birds – for example, swallows, swifts, flycatchers, and nightjars – have experienced particularly alarming population declines. In a new paper published Ecological Monographs, Dr. Sullivan and colleagues report their findings from a five-year study in Columbus, Ohio. This work looks at how climate, urbanization, and water quality interact to affect Tree Swallow reproductive success and condition. Tree Swallows were used as model aerial insectivorous bird.