Large flocks of American Crows (Corvus brachyrhynchos) form across Upstate New York each winter, eating in fields by day, gathering—and defecating—in urban roosts at night. Roosts can contain tens of thousands of crows, and can connect rural and urban habitats in important ways. We will study crows’ ecological impact on the landscape, specifically the movement of nutrients through fecal nitrogen deposited under roosts.