The Redpolls are a group of small passerine birds in the finch family Fringillidae which have characteristic red markings on their heads. They are very closely related, and taxonomically could be considered as any thing from one to five species. Recent studies tend to support three species.
* Common Redpoll, Carduelis flammea
* Lesser Redpoll, Carduelis cabaret
* Arctic Redpoll, Carduelis hornemanni
All redpolls are northern breeding woodland species, associated with birch trees. They are small dumpy birds, brown or grey-brown above and with a red forehead patch. The adult male's breast is washed in red, but in females and young birds the buff breast and white belly are streaked with brown. The bill is small and yellow. Some birds, particularly young ones, are difficult to assign to species.
They are primarily seed-eaters, and often feed acrobatically like a tit; their diet may include some insects in summer. They have a dry reeling song and a metallic call. They lay 4-7 eggs in a nest in a tree or, in the case of Arctic Redpoll, a large bush. They can form large flocks outside the breeding season, sometimes mixed with other finches.
Arctic Redpoll, Carduelis hornemanni, breeds in tundra birch forest. It has two races, C. h. hornemanni, (Greenland Arctic Redpoll) of Greenland and neighbouring parts of Canada, and C. h. exilipes, which breeds in the tundra of northern North America, where it is known as the Hoary Redpoll, and Eurasia. Many birds remain in the far north; some birds migrate short distances south in winter, sometimes travelling with Common Redpolls.
The Greenland race is a very large and pale bird, with the male sometimes described as a "snowball", but both forms are pale with small beaks, white rumps and often more yellow than grey-brown tones in their plumage. The females are more streaked on their breasts, sides and rumps, but are still pale.
Common Redpoll, Carduelis flammea, breeds somewhat further south than Arctic Redpoll, also in habitats with thickets or shrubs. Nominate C. f. flammea, breeds across the northern parts of North America and Eurasia. There is also an Icelandic race, C. f. islandica, and a race which breeds in Greenland and Baffin Island, C. f. rostrata. All forms migrate further south in winter into southern Canada, northern USA and most of Eurasia. These birds are remarkably resistant to cold temperatures and winter movements are mainly driven by the availability of food. Common Redpoll is smaller, browner and more streaked than Arctic.
Lesser Redpoll, Carduelis cabaret, is the smallest, brownest and most streaked species. It breeds in Ireland, Great Britain and neighbouring parts of Europe up to Norway, and the Alps. Many birds migrate further south in winter, but the milder climate means that this redpoll can be found all year round in much of its range, and may be joined by the other two species in winter. This species has been introduced to New Zealand.