It is a delight to encounter a flock of redpolls in late autumn and winter, and it’s always worth checking through them for the possibility of a scarce visitor from the Continent, in particular Mealy Redpoll.
The taxonomy of redpolls is fraught with difficulty, but in 2001 the BOU decided that Lesser Redpoll Carduelis cabaret and Mealy Redpoll C flammea should be regarded as separate species. There are three Mealy Redpoll subspecies: the nominate flammea breeds across the northern regions of Europe, Asia and North America, where it is known as Common Redpoll; Greater or Greenland Redpoll rostrata is found in southern Greenland; and Icelandic Redpoll islandica occurs in Iceland.
Many birds from Scandinavia tend to move into central Europe in winter, and some birds travel as far south as the Mediterranean. Adults and juveniles gather in flocks to moult before heading south and east. Good breeding seasons followed by a failure of the birch seed crop in favoured wintering areas can lead to sizeable irruptions from Scandinavia, with flocks of birds arriving in Britain, usually along the north and east coasts.
Mealy Redpolls can travel long distances on migration and birds ringed in China have been recovered in both Norway and Sweden, more than 4,000 miles away; European-ringed individuals have also been found in China. Birds from Greenland largely winter in Canada, the eastern United States and Iceland, while Icelandic breeders are mainly sedentary. Both Greenland and Icelandic Redpolls are very occasionally recorded in Britain, largely in northern and western Scotland and western Ireland.
In Britain, birds usually start to arrive in late September, continuing into November and remaining through the winter. Numbers vary, with only a few dozen in some years and hundreds in others. In 1910, more than 2,000 were seen in Lothian, and in October 1975 there were 500 on Fair Isle; more recently, there were 125 on Shetland in November 2010. Return passage can be seen in March and April. A few pairs of Mealy Redpolls have been found breeding in Shetland and Orkney and eight pairs bred in Sutherland in 2000. In the Outer Hebrides, birds have bred since the 1970s, with about 15 pairs in 2004, and these may have been Greenland or Icelandic Redpolls. Mealy Redpoll is a scarce winter visitor to Wales and Ireland, usually reported close to the coast.
Mealy Redpoll is one of the most hardy finches, able to survive in very cold conditions when sufficient food is available. In the far north of its range, it is known to sleep in snow tunnels. In spring and summer it feeds largely on spruce and Dwarf Birch, favouring other birch species in autumn and winter. Special sacs, known as diverticula, inside the birds’ throats are used for storing small seeds, enabling them to feed rapidly and then move to a sheltered and safe perch to actually shell and digest the food. A bird can store up to a quarter of its daily food requirement in these sacs. Redpolls can be attracted to feeders containing niger seed and millet. Always sociable, a flock of redpolls is known collectively as a ‘gallup’.
How to see
Check out any flocks of redpolls close to the east coast from October onwards, as Mealy Redpoll is often found associating with the commoner Lesser. It typically feeds in birch, willow and alder – watch out at any stands of these trees – as well on grass seeds. A flock is usually active and noisy, so listen out for the distinctive metallic chet chet call notes. As many of them come from the north of Scandinavia, they can be quite approachable and feed actively, often hanging upside down on small branches, using their feet to hold food items.
Where to watch
There are few regular sites for this species and in irruption years it can be encountered widely, even inland. Most records come from the north and west of Scotland and the east coast of England. The sites below have recorded birds on several occasions in recent years.
• Norfolk: Titchwell Marsh RSPB (TF
750438) and Wells Woods (TF 910454)
• East Yorkshire: Spurn Point (TA 419148)
• Suffolk: Landguard Point (TM 284319)
• Shetland: Fair Isle (HZ 221723)
• Orkney: North Ronaldsay (HY 785560)
• Outer Hebrides: Lewis (NB 424351)
• Argyll: Tiree (NL 960450)
October target bird: Mealy Redpoll