Mostly migratory; some birds resident in west of range. Races (nominate arquata, orientalis, and intergrades) mix in autumn and possibly in winter from Mediterranean basin eastwards to western coast of India.
Nominate arquata (breeding Europe east to Urals) probably largely resident in Ireland, with local movements to coast, though many also winter inland; movements unconfirmed in absence of ringing. Some British birds winter near breeding site, though most move south-west. Thus birds from Scotland and northern England move to British west coast and Ireland; those from southern England to south-west England, some to France and Iberia. Scandinavian population moves south-west: Norwegian birds to northern Britain, Ireland, and western France; main wintering area for Swedish birds is Britain and Ireland, though also some on Continental coasts from Denmark to western France. Recoveries of birds from Poland, Baltic States, Finland, and north-west Russia indicate similar south-west dispersal; many reach west European coast, including some to Britain and Ireland.
Main wintering area for German and Dutch birds is western France and Iberia, with some to Britain, Ireland, and Atlantic coast of Morocco. Birds wintering within Mediterranean basin are probably from central and south-east Europe (including Crimea and southern Russia): Swiss and Hungarian birds recovered in winter in Italy, Morocco, and Algeria. Banc d'Arguin (Mauritania) may be normal southern limit for European nominate arquata, though specimens claimed from Afrotropics as far south as Transvaal, South Africa. No recoveries to indicate origins of Mauritanian winter flocks.
Autumn passage of west European (including Fenno-Scandian) birds begins late June: adults arrive at North Sea estuaries (Wash, Waddenzee, East Frisian Wattenmeer) and commence moult; main arrivals in July-August. Birds leave breeding grounds in Alsace (France), West Germany, and Britain by mid-July ; in Russia, main departures July-August. Juveniles from Continent not present at the Wash (England) until mid- to late September; most long-distance movements by British juveniles take place August-October. Some birds (possibly adults) present Morocco by late July. Movements in eastern Europe continue into October-November. Most birds thought to winter at moulting grounds (Boere 1976; Bainbridge and Minton 1978); little evidence from recoveries of post-moulting movements. Winter locality fidelity probably strong: from coastal ringing, 81% of British birds recovered within 30 km. However, hard weather can cause unusual movements, e.g. movement in 1962-3 into France and Iberia from south-west England. Return migration by adults to western and southern breeding grounds in February-March: arrivals then in Britain, West Germany, Alsace, and Hungary. Many birds from Fenno-Scandia, Baltic States, and adjacent parts of Russia stay on European coasts until April-May. Main arrivals in northern Russia at end of April. Many 1st-year birds remain in winter quarters, and moult from May onwards. Most birds probably faithful to natal areas.
Nominate arquata and orientalis intergrade around Urals. Migration through Balkans includes both races and intermediates. Early 20th century records show no orientalis in Hungary, and all orientalis/arquata intergrades in Bulgaria, whereas records from 1950s and 1960s show c. 50% orientalis or orientalis/arquata in Albania, Hungary, and Rumania (but all birds in Austria and southern west Germany are nominate arquata). Hence migration of orientalis and intergrades believed to extend further west now than 40-80 years ago.
Typical orientalis (from Siberia), but with intergrades, believed to winter in part on east Mediterranean and Red Sea (where certainly occurs on passage); also across southern Asia from Persian Gulf to Philippines and Japan, and in Afrotropical and Malagasy regions. In Africa, orientalis occurs west to Gulf of Guinea, south to Cape Province, and much outnumbers nominate arquata claimed there from only a few specimens; however, composition of small flocks wintering Sénégal and Gambia unknown. Regular autumn occurrences, subspecies unknown, in Niger inundation zone (Mali), Nigerian Sahel, central Chad, and Nile valley in Sudan indicate trans-Saharan crossing from Mediterranean, perhaps diagonally from eastern basin.
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