Hypothesis-Based Analysis of the Effects of Supplemental Feeding on the Wintering Space Use of Whooper Swans (Cygnus cygnus)

Abstract

This study investigated the effects of supplemental feeding on the wintering spatial behavior of Whooper Swans (Cygnus cygnus) in South Korea by analyzing five spatial indicators: home range extent, spatial concentration, residence time, daily movement distance, and habitat use diversity. Using high-resolution Global Navigation Satellite System (GNSS) tracking data from two major sites—the Nakdong River Estuary (fed) and Junam Reservoir (unfed)—we examined how artificial feeding interacts with habitat structure and individual movement strategies. Contrary to the expectation that feeding reduces movement and increases site fidelity, swans in the fed estuary exhibited larger home ranges and shorter daily distances, but significantly lower habitat diversity. These results suggest that supplemental feeding improves energy efficiency while potentially promoting spatial fixation and ecological dependency, particularly in complex landscapes. The fed group showed fewer land cover types and lower Shannon diversity indices, indicating narrower habitat use and increased vulnerability to environmental changes or disease outbreaks. These findings emphasize the dual effects of feeding intervention and habitat heterogeneity on spatial behavior in migratory waterbirds. The results highlight the need for balanced wintering site management that accounts for both the energetic benefits and potential ecological risks of artificial feeding, with implications for conservation and disease prevention along the East Asian Flyway.