The Fragile First Year: GPS Tracking Identifies Post-Release Survival Risks in Migratory Geese.

Migratory birds play a critical role as sentinels of ecosystem health, serving as key indicator species for monitoring biodiversity changes and environmental conditions. The survival of migratory birds has always been a focus of attention, and the first year following post-release represents a critical period for establishing stable survival outcomes. However, it is difficult to track the life status of migratory birds, because some drivers affecting their survivorship may be hard to identify. Here, we investigated the survival and adaptation of Tundra Bean Geese () and Greater White-fronted Geese () by using GPS tracking data in order to systematically assess how study design parameters, key behavioral traits, and environmental conditions influence the first-year survival rates of migratory geese from post-release to spring migration onset. We found that the first-year survival probability was significantly affected by factors such as average daily activity levels and weather conditions, particularly wind speed. Notably, tracking device type also significantly influenced survival outcomes, with neckband tag units demonstrating superior performance compared to backpack tags. Contrary to expectations, geographic clusters showed no consistent survival times across study cohorts. These findings highlight the influences of study design parameters (particularly device selection), individual behavior, and local weather conditions on waterfowl survival time. Our results provide operational guidelines for GPS tracking deployment in geese conservation and are crucial for developing effective conservation strategies and management measures.