Survival During Migration and Winter

This chapter explores the patterns and drivers of waterfowl mortality and survival during the migration and winter periods, emphasizing how these dynamic life stages contribute to population regulation. Survival during these seasons varies widely across species, sexes, and age classes, influenced by energetic demands, environmental conditions, and behavioral strategies. Migration introduces heightened risk due to long-distance travel, exposure to unfamiliar environments, and limited opportunities for recovery. In winter, survival is shaped by habitat availability, food resources, disturbance, and weather severity. Major sources of mortality include harvest, predation, disease, and environmental stressors, though their relative influence often shifts depending on geography and time of year. The chapter underscores the difficulty of disentangling specific causes of mortality, particularly under natural conditions, and highlights the need for integrated monitoring approaches that combine banding, telemetry, and physiological metrics. Importantly, survival is not just a product of proximate threats but also of broader landscape dynamics and carry-over effects from prior seasons. Understanding how and when mortality occurs—and how it varies across space and taxa—is critical for linking habitat investments to demographic outcomes. The chapter calls for a more unified framework that incorporates survival into full annual cycle models and informs more effective conservation strategies.