Autumn migration of black-necked crane (Grus nigricollis) on the Qinghai-Tibetan and Yunnan-Guizhou plateaus.

ABSTRACT

Despite previous research efforts, the majority migration routes of the black-necked cranes (Grus nigricollis) have remained veiled. In this study, we utilized satellite telemetry data from 45 cranes between 2015 and 2021 to unveil critical insights. Our results revealed 11 distinct autumn migration routes and one sedentary flock, of which eight routes and the sedentary flock were previously undocumented. Our findings highlighted the remarkable diversity in the migration routes of black-necked cranes, especially in terms of migration orientations, spatial-temporal patterns, and altitudinal movement patterns. Cranes breeding on the eastern, northern, and central Qinghai-Tibetan Plateau migrated southward, while those on the northern slopes of the Himalayas migrated eastward, westward, northward, or opted to remain sedentary. Moreover, we expanded the known range of migration distances to 84-1520 km at both ends (excluding sedentary individuals) and identified two long-term (Da Qaidam and Chaka) and one short-term (Gyatong grassland) stopover sites. Furthermore, our study revealed that the breeding colonies in the Qilian Mountains on the northeastern Qinghai-Tibetan Plateau utilized long-term stopover sites before embarking on significant altitude ascent, while other flocks displayed more urgent migration patterns, preferring to roost only at night. By unveiling the near-complete autumn migration routes of black-necked cranes, our research has contributed to discovering the critical habitats and connectivity among various breeding colonies, which is instrumental in developing effective seasonal conservation plans.