Migration of Curlew Sandpiper Calidris ferruginea through the Azov–Black Sea region, Ukraine

The Sivash, the largest system of non-tidal lagoons in Europe, is a shallow bay of the Azov–Black Sea region, Ukraine. The total number of Curlew Sandpipers using the area on northward migration is estimated at 66,000 birds, and on southward migration possibly by as many as 160,000 birds. Peak northward migration was in the middle decade of May; from bill-length dynamics, it is clear that the passage of males was earlier than that of females. Although second calendar year birds are thought to remain in their non-breeding areas, substantial numbers were mistnetted on northward migration; from their bill lengths, most of these were males. Based on body mass, it seemed unlikely that Curlew Sandpipers departing the Sivash in May could reach the breeding grounds in the Taimyr Peninsula in one flight. Also, the interval between departure and arrival was about 20 days; it therefore seems likely that birds have an intermediate staging area. On southward migration, males arrived from mid-July, with mostly females from mid-August onwards. Juvenile passage started in the last decade of August, and continued through September. There are 78 ring recoveries either to or from the Ukraine. Birds on passage through the Ukraine are headed both to West Africa and to southern Africa. Some birds
appeared to perform a loop migration, travelling south through the Black Sea region and north along the western coast of Europe