IDENTIFICATION
Arctic Redpoll or Hoary Redpoll is medium size 13 to 14 cm large Arctic birds. It is representative of Common Redpoll (Acanthis flammea), which closely resembles species in the finch family Fringillidae. This is generally much whiter overall than dark southern race cabaret of Common (known as ‘Lesser Redpoll’) and large but dark race rostrata from S Greenland/Baffin is plus most individuals of the controversial Icelandic population.
There is a geographical variation under the Common Redpoll with the majority of individuals looking strikingly different. The classic Arctic of the large nominate race (a vagrant from Greenland or NE Canada) is very pale overall and unstreaked on both underparts and rump and is unlikely to be confused. The slightly larger size of nominate hornemanni is enhanced by its overall whiteness and by its softer, fluffier plumage, which often makes individuals look substantially bigger than Common of European races.
The main problem lies in separating the N European race of Arctic, exilipes, from the N European nominate race of Common (known as ‘Mealy Redpoll’) or from pale individuals belonging to the Icelandic population of Common (which look like a larger version of a pale ‘Mealy Redpoll’). ‘Mealy Redpolls’ are highly variable, and many individuals are very gray and pale in general appearance, leading to possible mistaken identity as the Arctic when they turn up in winter in flocks of southern ‘Lesser Redpolls’ (race cabaret).
Arctic Redpoll size is very similar, but structure differs subtly: exilipes Arctic tends to appear more compact and shorter-necked; plump appearance is enhanced by its softer, fluffier plumage. The Arctic also has, on average, a proportionately shorter, deeper-based, squatter-looking bill with a straighter culmen, but there is extensive overlap.
In comparison with typical nominate Common, typical exilipes Arctic is almost lacking in brown or buff tones in plumage, being basically gray and white, and has an unstreaked white band on the rump that sometimes extends to the back, only weak dark streaking on flanks and sides of breast, and conspicuously white greater covert bar and fringes to wing feathers.
Arctic Redpoll typically shows a broad white unstreaked rump patch (tinged pale pink in adult males in spring/summer). Nominate Common typically shows a grayish-white or buffy-white rump patch (tinged pink in adult males in spring/summer) which is diffusely streaked throughout, but some individuals have a distinctive white rump patch and some adult males may have part of rump unstreaked, while some Arctic, particularly females, have faint streaking in the rump patch (especially when heavily worn in late spring/summer).
The Arctic typically exhibits only weak, sparse, and rather pale dark streaking on sides of breast and flanks (in adult males often restricted to breast sides, or occasionally even lacking). Common is usually noticeably more heavily streaked on the sides of the breast and flanks, the streaks being darker, denser, and longer and tending to form stripes on flanks. Some adult male Common show only weak streaking on sides of breast and on fore-flanks, but rear flanks typically heavily streaked.
Some Arctics (probably mainly 1st-years) are more heavily streaked, however, and are thus close to Common. Arctic’s undertail coverts (which can sometimes be observed as birds feed in the outer canopy of trees and bushes) are either all-white or else have a narrow dark (grayish) central streak on the longest feathers (i.e. those projecting furthest).
Common Redpoll frequently shows a broad dark (blackish) central streak on the longest pair of undertail coverts and narrower dark central streaks on the remainder, but occasional adult males have these streaks weak or even lacking. Some exilipes Arctics, especially adult females or 1st-years in fresh plumage in autumn/winter, have a pale yellowish-buff suffusion on sides of face and breast which differs subtly from the brownish-buff suffusion of many nominate Commons, but as usual, there is some overlap.
The head pattern often differs, Arctic Redpoll tending to have weakly streaked nape and ear-coverts, and abroad, almost unstreaked, pale supercilium, Common tending to have all these areas heavily streaked, with darker ear-coverts contrasting with the narrow pale supercilium. Mantle/scapulars average paler and grayer in Arctic Redpoll, however, Common Redpoll averaging darker and browner, with heavier dark streaking, but note that coloration varies with age, sex, and wear: fresh adults are palest and least heavily streaked (males most of all).
In fresh plumage (autumn onwards), Arctic Redpoll tends to show broader white fringes to wing coverts, tertials, and flight feathers, and a more obvious white wing bar (formed by broader white tips to greater coverts), but this difference is diminished by wear. In addition, adult male Arctic in spring/summer has only a rather weak pink flush on breast and rump while adult male Common in spring/summer usually has strong pink or pinkish-red suffusion on breast and often sides of the head, flanks, and rump.
Moreover, some adult female Common is close to males in the extent of pink suffusion, while female Arctics and some males in their first spring/summer generally lack pink. Some Arctic (probably 1st-years) is noticeably darker on upperparts and more heavily streaked on flanks and sides of breast. Such birds may have faint streaking on the rump (and also fairly obvious dark central streaks on the longest undertail coverts), making them especially difficult to separate from some nominate race Common.
Juveniles are tinged buffish on mantle, sometimes also on wing bars, so are still more problematic. Careful assessment of all the field characters should allow most individuals to be identified correctly. But, with some degree of overlap occurring in all field characters, there will always be some redpolls that are not specifically identifiable. And indeed in northern Scandinavia, where the two species overlap, hybridization (possibly on quite a large scale) has been recorded. The significance of this hybridization as regards field identification of redpolls has not yet been fully assessed.
SEX/AGE
Much as Common Redpoll 1st-years resemble respective adults but have buffish wash to mantle when fresh in autumn/winter.
VOICE/CALL/SONG
Arctic Redpoll call and song are very much as Common Redpoll. The twitter call may be slightly slower and higher-pitched, and the ringing whistle given when perched sounds hoarser and more hesitant to some ears, falling slightly rather than rising at the end.
TAXONOMY
Hybridization in N Europe and elsewhere has led some taxonomists to suggest that the redpolls are just one species (C. flammea) consisting of a large group of variable subspecies. Others suggests that 3–4 species are involved.
GEOGRAPHICAL VARIATION
Moderate. 2 races (both illustrated). The breeding form of our region is exilipes. The nominate race, which breeds in Greenland and arctic Canada, is only a vagrant to NW Europe; this race is larger than the breeding form, with a wing length of 79–88 mm (against 68–78 mm in exilipes), and is the whiter of the two, with a wider pale rump band and less streaking on the flanks.
HABITAT
Arctic Redpoll is not uncommon. Breeds in arctic tundra scrub such as dwarf willows, birches, etc. Outside breeding season, it may be encountered in similar habitats to those frequented by Common Redpoll, with which it sometimes forms mixed flocks.
