Large-scale movements of Dunlin breeding in Chukotka, Russia, during the non-breeding period

Many shorebird populations have declined, and mapping habitat use during the non-breeding period and determining timing of use have become increasingly urgent for conservation. This study provides the first detailed location information on the complete migration cycle for the subspecies of Dunlin Calidris alpina sakhalina breeding in Chukotka, Russia. Geolocators were deployed and recovered on breeding Dunlin at Chaun River Delta (n = 12 of 35 deployed) and Belyaka Spit, Russia (n = 11 of 25 deployed), between 2011 and 2014. Dunlin migrated south through the Sea of Okhotsk to the Korean Peninsula and China. Upon reaching the Yellow Sea, ten individuals stopped for 39–74 (mean ± SE; 54 ± 4) days before moving on to wintering grounds in China, and two remained in the area throughout the winter. Tagged Dunlin wintered in China, South Korea, and Vietnam, primarily between the northwest Yellow Sea and the Gulf of Tonkin in China. Nine individuals moved from their wintering grounds north to areas around the Yellow Sea between 10 March and 3 April (mean: 23 March), where they spent 23–73 (53 ± 4) days before continuing to the Arctic breeding grounds with only short stopovers (<10 days). Dunlin may be site-faithful to their winter and stopover areas; geolocators on three individuals recorded >1 year of data and indicated very similar migratory routes and use of winter areas between years. At the scale of this study, there was no segregation of Dunlin that bred in the Chaun River Delta and at Belyaka Spit during the non-breeding season. Dunlin breeding in Chukotka, Russia, are particularly reliant on coastal habitat around the Yellow Sea, as well as the Fujian coast and Yangtze River floodplain in China for wintering habitat. The Yellow Sea is an important stopover site during both southern and northern migrations, as are coastal areas around northern Sakhalin Island and the Sea of Okhotsk.