Migration of Curlew Sandpipers Calidris ferruginea in southern Central Siberia

Curlew Sandpiper studies were undertaken in southern Central Siberia over the period 1980–2003. Most records on northward migration were in the final decade of May and early June; few birds were recorded. The peak of southward migration for adults was 16–25 July, and for juveniles was 20 August–4 September. As many as 20,000 birds could be in the region at the time of peak migration of juveniles, and the total number of Curlew Sandpipers on southward migration in years of successful breeding is estimated as being at least 35,000–40,000 birds. Migration was on a wide front, across the entire region. On southward migration, stopover duration averaged 5.3 days for adults 3.8 days for juveniles; birds concentrated on the steppe lakes and seldom occurred on water bodies in the taiga zone. The average rates of body mass gain was 4.1 g per day in adults and 1.2 g per day in juveniles. In adults, no moult was recorded for primaries or remiges, but most adults were migrating with body feather tracts in moult, and the moult of males was slightly more advanced than females. No moult was found in juveniles. The breeding grounds of Curlew Sandpipers on passage through the region are not known; ring recoveries provide migratory links with Australian nonbreeding grounds.