The North American Breeding Bird Survey indicates a long-term decline of the Dark-eyed Junco (Junco hyemalis). Strong flock fidelity and small overwinter home range of juncos makes them exceptional models for studies investigating seasonal mortality. Using varied food supply, I measured the site persistence of supplemented and unsupplemented flocks after a 60-day period using mark and resight methods. The effect of food supplementation on overwinter site persistence was statistically significant in 2011, 2012, and 2013. Additionally, average daily temperature, snowfall, and snow accumulation significantly decreased persistence among unsupplemented flocks in cold winters (2011, 2013) compared to mild winters (2012). The expectation from literature is that absentee birds represent mortality rather than dispersal. Increased overwinter survival may reverse decline.