All of the Winter Thrushes Survey study species are strong seasonal migrants but many are also resident in parts of their breeding ranges. Britain's mild winters, relative to most of Europe, attract copious winter visitors to join our mainly resident populations: these are mainly of three species – Blackbird, Redwing and Fieldfare.
Britain holds a very large breeding population of Blackbirds. Most British-bred birds show very restricted seasonal movements and it is rare for them to visit the European continent. By contrast, Blackbirds breeding in upland or northerly parts of Fenno-Scandia and from Poland eastward into Ukraine and western Russia almost all migrate long distances to find milder winter climates. Birds from Norway and the Baltic region show a strong westerly component to autumn movements, wintering in big numbers from Britain and Ireland south to Spain, with some reaching North Africa and even Iceland.
Arrivals can be expected between September and November and some continental birds will still be in Britain in April.
Blackbirds do not occur in the northern Russian forests but there are further populations in south Asia and the species has non-native populations in Australia and New Zealand.
Fieldfares have a wide breeding range, extending from France and Norway broadly across Europe and Asia and almost reaching the southeast coast of Russia. Only a few isolated instances of nesting have been recorded in Britain and Iceland. There is a major shift westward in winter and almost all wintering areas are in the Western Palaearctic. Countries with an Atlantic seaboard are important winter destinations for birds from as far east as central Siberia. Most that winter in Britain and Ireland (and probably those wintering in Iceland) are from Scandinavia, Finland or northwest Russia, but some might be from very much further east.
The very first Fieldfares often arrive in mid August but the big arrivals begin generally around the end of September. Spring migration is evident throughout April and often into early May.
Redwing, like Fieldfare, has a wide breeding distribution across northern Eurasia which condenses westwards into the Western Palaearctic for the winter period. It is a common summer bird in Iceland, where (apart from sporadic Blackbirds and Fieldfares) it is the only breeding thrush. Northern Scotland has a small and apparently dwindling breeding population. The race coburni, from Iceland and the Faroe Islands, winters almost exclusively in Scotland, Ireland, western France and western Iberia. Nominate-race birds breeding from Norway to east of the Ural Mountains winter far more widely in western Europe.
A few Redwings sometimes arrive in August but the main arrivals occur in late September and October. At migration times, the species' distinctive flight calls can frequently be heard overhead – most easily at night when ambient noise levels are reduced. Spring migrants are often present up to mid April and sometimes into May.
Ring Ouzel is a breeding bird of rocky slopes and high moorland. Its nominate race breeds in Ireland and Britain and along the mountain spine of Scandinavia from southern Norway to the Kola Peninsula in northwest Russia. In Britain it has a patchy and diminishing range from Dartmoor to northwest Scotland. These birds winter mainly in southern Spain and the Atlas Mountains of North Africa. Migrating Ring Ouzels, many of them from Scandinavia, are frequently seen in Britain well into November, sometimes in company with Redwings and Fieldfares, but are then mostly absent until the first breeders return in late March. Spring passage is noted mainly in April and early May.
Another race, alpestris, breeds along Europe's main watersheds from northern Spain through the Alps to the Appennines, Balkans and Carpathians, and a third race, amicorum, in Turkey, the Caucasus and western Kazakhstan.
This large thrush breeds from Morocco, Ireland and Norway east to Lake Baikal, western Mongolia and western Nepal. The western, nominate race is replaced by bonapartei in central Siberia and the mountains of central Asia, and by deichleri in northwest Africa, Corsica and Sardinia. In Europe, the entire northeast of the breeding range is deserted in winter as birds move towards Morocco, Iberia and the Mediterranean and Black Sea basins. Scandinavian birds are all migratory, wintering mainly between Belgium and northern Spain. All this migratory activity passes Britain by almost completely, although tiny numbers of migrants are recorded in autumn and spring, especially near the east coast. Our breeding population makes very little seasonal movement, although ringing shows that some birds, perhaps driven by hard winter weather, reach Ireland and France.
Song Thrushes breed very widely across the Palaearctic from Iberia, Ireland and Norway eastwards to northern Iran and western Mongolia. There are non-native populations in Australia and New Zealand. Its winter range is more southerly than the other west Siberian thrush species, extending well south into Africa in Mauritania, Egypt and Djibouti and into southern Iran and the Gulf States. British breeders comprise the races hebridensis in the Western Isles and Isle of Skye and clarkei elsewhere, with clarkei also nesting in Ireland and on the near Continent. Many clarkei leave Britain for Ireland, France or Iberia for the winter, although most show little seasonal movement unless prompted by severe weather. Hard winter weather can also bring birds from the Netherlands and Belgium into Britain.
The massive migration of nominate-race birds on the Continent can sometimes be evident across Britain in autumn, and is known to involve birds from as far east as Finland. It is rarely possible to distinguish this, however, from movements of local birds. Occasional continental individuals are reported in winter but it is clear that a high proportion of them continue further south, to at least France or Iberia. Return movements of continental birds in spring are also evident in Britain but at an even smaller scale.
The Waxwing is well known for its erratic movements, which in some years bring almost no birds to Britain and in others tens of thousands. Its breeding range extends throughout the boreal forest zone, from Norway to Kamchatka and from Alaska to Hudson Bay. Three races are described – nominate garrulus in Europe and western Siberia, centralasiae in central and eastern Siberia, and pallidiceps in North America. The origin of British arrivals, when they do come, is still a matter for conjecture! Ringing results indicate that many come from Finland and European Russia but birds from central Siberia are also known to visit western Europe.
Waxwing is only very distantly related to thrushes and is not a main target of the Winter Thrushes Survey. Because it so often feeds alongside thrushes, however, there are options to record any that observers are lucky enough to see. There have been several good winters for Waxwings recently and many were recorded on WTS routes during the survey's first winter.
Starling is not a thrush but, because they so often feed in mixed groups with thrushes in fields and on hedges, the Winter Thrushes Survey includes options for recording this species also. Starling's native breeding range extends from northern Spain, Ireland and Iceland eastwards to western Mongolia and Pakistan. Introduced populations occur widely in North America, Australia and New Zealand. Nominate-race birds breed throughout Britain but are replaced in Shetland by the endemic race zetlandicus. Autumn brings large arrivals of nominate vulgaris from northern Europe, many from well into Russia. Like British breeding Starlings, though, the winter immigrants have declined very steeply over recent decades. New information on where these birds are feeding may further their future conservation.