Abstract: In recent years, Chongming Dongtan has become an important overwintering ground for Tundra Swan (Cygnus columbianus) in China. It is therefore of great significance to understand their migration routes and patterns for the cross-regional joint protection of migratory birds. During February to December in 2022, 10 individuals of Tundra Swan were satellite-tracked in Chongming Dongtan and 1336688 positioning data points were collected. We identified three migration routes for Tundra Swan wintering in Chongming Dongtan to the west, middle and east. The middle route along the southern coast of the Kara Sea in Krasnoyarsk Krai, Russia was a new record. The wintering grounds of Tundra Swan were widely spread in Anhui, Jiangxi, Shanghai and some other places. The migration duration and stopover times of overwintering Tundra Swan in Chongming Dongtan in spring were significantly higher than those in autumn, while the migration speed was significantly lower than that in autumn, indicating that spring migration process was slower than that in autumn. In spring migration, the averaged duration was 107.9±31.8 d, and the averaged distance was 5805.7±648.2 km at the average flight speed of 1256.2±385.3 km·d^-1 and the averaged stopover times of 13.7±3.7. The autumn migration lasted 61.3±15.3 d, and the birds traveled 5348.5±705.9 km at the average flight speed of 1014.3±335.7 km·d^-1 and the averaged stopover times of 6.0±1.9. We updated the important stopovers along the migration routes, including the Yellow River wetlands in Inner Mongolia and the Luanhe River valley in Zhangjiakou, Hebei Province. Our results will help judge the current situation of the overwintering Tundra Swan population and its habitat in China, so as to adopt reasonable monitoring and management measures for conservation.

Key words: Cygnus columbianus, satellite tracking, migration route, stopover site, migration characteristic