Differences in migration strategies between rescued juvenile and adult Oriental white storks (Ciconia boyciana) and the conservation implications

Abstract The Oriental white stork (Ciconia boyciana), with a global population of roughly 2500, is listed as endangered by IUCN. To date, little is known about its behaviors, particularly on migration, habitat use and their ontogenic differences. In this study, we tracked 11 Oriental White storks (9 juveniles and 2 adults) rescued in Sanjiang Plain and investigated their migration behaviors and survival rates using GPS/GSM telemetry. The results show that all the rescued individuals joined the wild migrating groups, but the migration routes of juvenile birds are highly variable compared to adult ones. From its breeding grounds of the Songnen/Sanjiang Plains to the wintering grounds in middle reaches of the Yangtze River, there is no significant correlation in habitat selections by adult birds, as wetlands being their first choice. In contrast, a positive correlation in juveniles’ selection has been identified over artificial habitats such as rice paddies and fish farms，which could lead to human-wild conflicts and affect the survival of juvenile storks. In this study, eight out of nine juveniles dies in the end of tracking. Our study exposes negative consequences of inappropriate release of rescued wild animals (especially juveniles) on species survival, and thus provides scientific guidelines to the future situations alike. Moreover, it is necessary to reduce the direct contact between humans and rescued animals, so that their dependence on artificial environments could be reduced, which could benefit the species’ long term survival, especially for the rescued population.